diff --git a/addons/crm/data/crm_lead_demo.xml b/addons/crm/data/crm_lead_demo.xml
index 8ef7a215796..1c49f1180b1 100644
--- a/addons/crm/data/crm_lead_demo.xml
+++ b/addons/crm/data/crm_lead_demo.xml
@@ -134,6 +134,7 @@
             <field name="priority">2</field>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(weeks=2)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="stage_lead1"/>
             <field name="description"></field>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
@@ -173,6 +174,7 @@ Contact: +1 813 494 5005</p>]]></field>
             <field name="priority">2</field>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(weeks=2)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="stage_lead1"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_services"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -195,6 +197,7 @@ Contact: +1 813 494 5005</p>]]></field>
             <field name="priority">0</field>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(weeks=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="stage_lead1"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -216,6 +219,7 @@ Contact: +1 813 494 5005</p>]]></field>
             <field name="priority">1</field>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=5)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="stage_lead1"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -251,6 +255,7 @@ ESM Expert<br />]]></field>
             <field name="priority">2</field>
             <field name="team_id" ref="sales_team.crm_team_1"/>
             <field name="user_id" ref="base.user_demo"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=4)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="stage_lead1"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -272,6 +277,7 @@ ESM Expert<br />]]></field>
             <field name="priority">2</field>
             <field name="team_id" ref="sales_team.crm_team_1"/>
             <field name="user_id" ref="base.user_demo"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=2)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="stage_lead1"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -307,6 +313,7 @@ Andrew</p>]]></field>
             <field name="priority">2</field>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="stage_lead1"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -356,6 +363,7 @@ Andrew</p>]]></field>
             <field name="date_deadline" eval="(DateTime.today() + relativedelta(months=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(weeks=3)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead1"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="medium_id" ref="utm.utm_medium_email"/>
@@ -382,6 +390,7 @@ Andrew</p>]]></field>
             <field name="date_deadline" eval="(DateTime.today() + relativedelta(months=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="team_id" ref="sales_team.crm_team_1"/>
             <field name="user_id" ref="base.user_demo"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(weeks=2)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead1"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="medium_id" ref="utm.utm_medium_website"/>
@@ -405,6 +414,7 @@ Andrew</p>]]></field>
             <field name="date_deadline" eval="(DateTime.today() + relativedelta(months=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(weeks=2)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead2"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_services"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -494,6 +504,7 @@ Andrew</p>]]></field>
             <field name="date_deadline" eval="DateTime.today().strftime('%Y-%m-%d %H:%M')"/>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(weeks=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead2"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -519,6 +530,7 @@ Andrew</p>]]></field>
             <field name="date_deadline" eval="(DateTime.today() + relativedelta(months=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="team_id" ref="sales_team.crm_team_1"/>
             <field name="user_id" ref="base.user_demo"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(weeks=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead2"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="medium_id" ref="utm.utm_medium_website"/>
@@ -552,6 +564,7 @@ Andrew</p>]]></field>
             <field name="date_deadline" eval="(DateTime.today() + relativedelta(months=2)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="team_id" ref="sales_team.crm_team_1"/>
             <field name="user_id" ref="base.user_demo"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(weeks=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead2"/>
             <field eval="1" name="active"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_services"/>
@@ -602,6 +615,7 @@ Andrew</p>]]></field>
             <field name="date_deadline" eval="(DateTime.today() + relativedelta(weeks=1)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="team_id" ref="sales_team.crm_team_1"/>
             <field name="user_id" ref="base.user_demo"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=5)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead3"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -626,6 +640,7 @@ Andrew</p>]]></field>
             <field name="date_deadline" eval="DateTime.today().strftime('%Y-%m-%d %H:%M')"/>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=5)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead3"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_services"/>
             <field name="source_id" ref="utm.utm_source_mailing"/>
@@ -646,6 +661,7 @@ Andrew</p>]]></field>
             <field name="priority">2</field>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=5)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead3"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_services"/>
             <field name="medium_id" ref="utm.utm_medium_phone"/>
@@ -665,6 +681,7 @@ Andrew</p>]]></field>
             <field name="priority">1</field>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=3)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead3"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="medium_id" ref="utm.utm_medium_email"/>
@@ -683,6 +700,7 @@ Andrew</p>]]></field>
             <field name="date_deadline" eval="DateTime.today().strftime('%Y-%m-%d %H:%M')"/>
             <field name="team_id" ref="sales_team.crm_team_1"/>
             <field name="user_id" ref="base.user_demo"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=3)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead3"/>
             <field name="campaign_id" ref="utm.utm_campaign_fall_drive"/>
             <field name="medium_id" ref="utm.utm_medium_direct"/>
@@ -703,6 +721,7 @@ Andrew</p>]]></field>
             <field name="tag_ids" eval="[(6, 0, [ref('sales_team.categ_oppor7')])]"/>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=3)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead3"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="medium_id" ref="utm.utm_medium_website"/>
@@ -727,6 +746,7 @@ Andrew</p>]]></field>
             <field name="tag_ids" eval="[(6, 0, [ref('sales_team.categ_oppor4')])]"/>
             <field name="team_id" ref="sales_team.team_sales_department"/>
             <field name="user_id" ref="base.user_admin"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=2)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead3"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_services"/>
             <field name="medium_id" ref="utm.utm_medium_phone"/>
@@ -750,6 +770,7 @@ Andrew</p>]]></field>
             <field name="tag_ids" eval="[(6, 0, [ref('sales_team.categ_oppor2')])]"/>
             <field name="team_id" ref="sales_team.crm_team_1"/>
             <field name="user_id" ref="base.user_demo"/>
+            <field name="date_open" eval="(DateTime.today() - relativedelta(days=2)).strftime('%Y-%m-%d %H:%M')"/>
             <field name="stage_id" ref="crm.stage_lead3"/>
             <field name="campaign_id" ref="utm.utm_campaign_email_campaign_products"/>
             <field name="medium_id" ref="utm.utm_medium_website"/>
@@ -816,7 +837,7 @@ Andrew</p>]]></field>
             <field name="phone">+33 1 25 54 45 69</field>
             <field name="tag_ids" eval="[(6, 0, [ref('sales_team.categ_oppor6')])]"/>
             <field name="priority">1</field>
-            <field name="date_open" eval="(DateTime.today() - relativedelta(months=2)).strftime('%Y-%m-%d %H:%M')"/>
+            <field name="date_open" eval="False"/>
             <field name="team_id" eval="False"/>
             <field name="user_id" eval="False"/>
             <field name="stage_id" ref="stage_lead2"/>
@@ -840,7 +861,7 @@ Andrew</p>]]></field>
             <field name="phone">+32 22 33 54 07</field>
             <field name="tag_ids" eval="[(6, 0, [ref('sales_team.categ_oppor6')])]"/>
             <field name="priority">1</field>
-            <field name="date_open" eval="(DateTime.today() - relativedelta(months=2)).strftime('%Y-%m-%d %H:%M')"/>
+            <field name="date_open" eval="False"/>
             <field name="team_id" eval="False"/>
             <field name="user_id" eval="False"/>
             <field name="stage_id" ref="stage_lead1"/>
diff --git a/addons/crm/models/crm_lead.py b/addons/crm/models/crm_lead.py
index 068f1623bdd..4d11d354b29 100644
--- a/addons/crm/models/crm_lead.py
+++ b/addons/crm/models/crm_lead.py
@@ -297,7 +297,8 @@ class Lead(models.Model):
                 continue
             team_domain = [('use_leads', '=', True)] if lead.type == 'lead' else [('use_opportunities', '=', True)]
             team = self.env['crm.team']._get_default_team_id(user_id=user.id, domain=team_domain)
-            lead.team_id = team.id
+            if lead.team_id != team:
+                lead.team_id = team.id
 
     @api.depends('user_id', 'team_id', 'partner_id')
     def _compute_company_id(self):
@@ -345,12 +346,14 @@ class Lead(models.Model):
     @api.depends('user_id')
     def _compute_date_open(self):
         for lead in self:
-            lead.date_open = self.env.cr.now() if lead.user_id else False
+            if not lead.date_open and lead.user_id:
+                lead.date_open = self.env.cr.now()
 
     @api.depends('stage_id')
     def _compute_date_last_stage_update(self):
         for lead in self:
-            lead.date_last_stage_update = self.env.cr.now()
+            if not lead.date_last_stage_update:
+                lead.date_last_stage_update = self.env.cr.now()
 
     @api.depends('create_date', 'date_open')
     def _compute_day_open(self):
@@ -767,13 +770,27 @@ class Lead(models.Model):
         if vals.get('website'):
             vals['website'] = self.env['res.partner']._clean_website(vals['website'])
 
-        stage_updated, stage_is_won = vals.get('stage_id'), False
-        # stage change: update date_last_stage_update
-        if stage_updated:
-            stage = self.env['crm.stage'].browse(vals['stage_id'])
-            if stage.is_won:
-                vals.update({'probability': 100, 'automated_probability': 100})
-                stage_is_won = True
+        now = self.env.cr.now()
+        stage_updated, stage_is_won = False, False
+        # stage change (or reset): update date_last_stage_update if at least one
+        # lead does not have the same stage
+        if 'stage_id' in vals:
+            stage_updated = any(lead.stage_id.id != vals['stage_id'] for lead in self)
+            if stage_updated:
+                vals['date_last_stage_update'] = now
+            if stage_updated and vals.get('stage_id'):
+                stage = self.env['crm.stage'].browse(vals['stage_id'])
+                if stage.is_won:
+                    vals.update({'probability': 100, 'automated_probability': 100})
+                    stage_is_won = True
+        # user change; update date_open if at least one lead does not
+        # have the same user
+        if 'user_id' in vals and not vals.get('user_id'):
+            vals['date_open'] = False
+        elif vals.get('user_id'):
+            user_updated = any(lead.user_id.id != vals['user_id'] for lead in self)
+            if user_updated:
+                vals['date_open'] = now
 
         # stage change with new stage: update probability and date_closed
         if vals.get('probability', 0) >= 100 or not vals.get('active', True):
@@ -1432,7 +1449,12 @@ class Lead(models.Model):
             if merged_data.get('stage_id') not in team_stage_ids.ids:
                 merged_data['stage_id'] = team_stage_ids[0].id if team_stage_ids else False
 
-        # write merged data into first opportunity
+        # write merged data into first opportunity; remove some keys if already
+        # set on opp to avoid useless recomputes
+        if 'user_id' in merged_data and opportunities_head.user_id.id == merged_data['user_id']:
+            merged_data.pop('user_id')
+        if 'team_id' in merged_data and opportunities_head.team_id.id == merged_data['team_id']:
+            merged_data.pop('team_id')
         opportunities_head.write(merged_data)
 
         # delete tail opportunities
@@ -1686,7 +1708,6 @@ class Lead(models.Model):
         new_team_id = team_id if team_id else self.team_id.id
         upd_values = {
             'type': 'opportunity',
-            'date_open': self.env.cr.now(),
             'date_conversion': self.env.cr.now(),
         }
         if customer != self.partner_id:
diff --git a/addons/crm/tests/test_crm_lead.py b/addons/crm/tests/test_crm_lead.py
index 3e975ffb5bc..6627838f352 100644
--- a/addons/crm/tests/test_crm_lead.py
+++ b/addons/crm/tests/test_crm_lead.py
@@ -3,6 +3,7 @@
 
 from datetime import datetime
 from freezegun import freeze_time
+from unittest.mock import patch
 
 from odoo import fields
 from odoo.addons.base.tests.test_format_address_mixin import FormatAddressCase
@@ -561,11 +562,23 @@ class TestCRMLead(TestCrmCommon):
 
     @users('user_sales_manager')
     def test_crm_lead_stages(self):
-        lead = self.lead_1.with_user(self.env.user)
-        self.assertEqual(lead.team_id, self.sales_team_1)
+        first_now = datetime(2023, 11, 6, 8, 0, 0)
+        with patch.object(self.env.cr, 'now', lambda: first_now), \
+             freeze_time(first_now):
+            self.lead_1.write({'date_open': first_now})
 
-        lead.convert_opportunity(self.contact_1)
+        lead = self.lead_1.with_user(self.env.user)
+        self.assertEqual(lead.date_open, first_now)
         self.assertEqual(lead.team_id, self.sales_team_1)
+        self.assertEqual(lead.user_id, self.user_sales_leads)
+
+        second_now = datetime(2023, 11, 8, 8, 0, 0)
+        with patch.object(self.env.cr, 'now', lambda: second_now), \
+             freeze_time(second_now):
+            lead.convert_opportunity(self.contact_1)
+        self.assertEqual(lead.date_open, first_now)
+        self.assertEqual(lead.team_id, self.sales_team_1)
+        self.assertEqual(lead.user_id, self.user_sales_leads)
 
         lead.action_set_won()
         self.assertEqual(lead.probability, 100.0)
@@ -636,6 +649,96 @@ class TestCRMLead(TestCrmCommon):
         self.assertEqual(self.contact_company_1.email, 'broken')
         self.assertEqual(self.contact_company_1.phone, 'alsobroken')
 
+    @users('user_sales_manager')
+    def test_crm_lead_update_dates(self):
+        """ Test date_open / date_last_stage_update update, check those dates
+        are not erased too often """
+        first_now = datetime(2023, 11, 6, 8, 0, 0)
+        with patch.object(self.env.cr, 'now', lambda: first_now), \
+             freeze_time(first_now):
+            leads = self.env['crm.lead'].create([
+                {
+                    'email_from': 'testlead@customer.company.com',
+                    'name': 'Lead_1',
+                    'team_id': self.sales_team_1.id,
+                    'type': 'lead',
+                    'user_id': False,
+                }, {
+                    'email_from': 'testopp@customer.company.com',
+                    'name': 'Opp_1',
+                    'type': 'opportunity',
+                    'user_id': self.user_sales_salesman.id,
+                },
+            ])
+            leads.flush_recordset()
+        for lead in leads:
+            self.assertEqual(lead.date_last_stage_update, first_now,
+                             "Stage updated at create time with default value")
+            self.assertEqual(lead.stage_id, self.stage_team1_1)
+            self.assertEqual(lead.team_id, self.sales_team_1)
+        self.assertFalse(leads[0].date_open, "No user -> no assign date")
+        self.assertFalse(leads[0].user_id)
+        self.assertEqual(leads[1].date_open, first_now, "Default user assigned")
+        self.assertEqual(leads[1].user_id, self.user_sales_salesman, "Default user assigned")
+
+        # changing user_id may change team_id / stage_id; update date_open and
+        # maybe date_last_stage_update
+        updated_time = datetime(2023, 11, 23, 8, 0, 0)
+        with patch.object(self.env.cr, 'now', lambda: updated_time), \
+             freeze_time(updated_time):
+            leads.write({"user_id": self.user_sales_salesman.id})
+            leads.flush_recordset()
+        for lead in leads:
+            self.assertEqual(lead.stage_id, self.stage_team1_1)
+            self.assertEqual(lead.team_id, self.sales_team_1)
+        self.assertEqual(
+            leads[0].date_last_stage_update, first_now,
+            'Setting same stage when changing user_id, should not update')
+        self.assertEqual(
+            leads[0].date_open, updated_time,
+            'User assigned -> assign date updated')
+        self.assertEqual(
+            leads[1].date_last_stage_update, first_now,
+            'Setting same stage when changing user_id, should not update')
+        self.assertEqual(
+            leads[1].date_open, updated_time,
+            'Should not update date_open, was already the same user_id, but done in batch so ...')
+
+        # set won changes stage -> update date_last_stage_update
+        newer_time = datetime(2023, 11, 26, 8, 0, 0)
+        with patch.object(self.env.cr, 'now', lambda: newer_time), \
+             freeze_time(newer_time):
+            leads[1].action_set_won()
+            leads[1].flush_recordset()
+        self.assertEqual(
+            leads[1].date_last_stage_update, newer_time,
+            'Mark as won updates stage hence stage update date')
+        self.assertEqual(leads[1].stage_id, self.stage_gen_won)
+
+        # merge may change user_id and then may change team_id / stage_id; in this
+        # case no real value change is happening
+        last_time = datetime(2023, 11, 29, 8, 0, 0)
+        with patch.object(self.env.cr, 'now', lambda: last_time), \
+             freeze_time(last_time):
+            leads.merge_opportunity(
+                user_id=self.user_sales_salesman.id,
+                auto_unlink=False,
+            )
+            leads.flush_recordset()
+        self.assertEqual(leads[0].date_last_stage_update, first_now)
+        self.assertEqual(leads[0].date_open, updated_time)
+        self.assertEqual(leads[0].stage_id, self.stage_team1_1)
+        self.assertEqual(leads[0].team_id, self.sales_team_1)
+        self.assertEqual(
+            leads[1].date_last_stage_update, newer_time,
+            'Should not rewrite when setting same stage')
+        self.assertEqual(
+            leads[1].date_open, updated_time,
+            'Should not rewrite when setting same user_id')
+        self.assertEqual(leads[1].stage_id, self.stage_gen_won)
+        self.assertEqual(leads[1].team_id, self.sales_team_1)
+        self.assertEqual(leads[1].user_id, self.user_sales_salesman)
+
     @users('user_sales_manager')
     def test_crm_team_alias(self):
         new_team = self.env['crm.team'].create({