diff --git a/scripts/_common.sh b/scripts/_common.sh
index c0f76ae..bfeba57 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -27,6 +27,31 @@ log_file="${log_path}/pyinventory.log"
 # dependencies used by the app
 pkg_dependencies="build-essential python3-dev python3-pip python3-venv git libpq-dev postgresql postgresql-contrib libjpeg-dev"
 
+#=================================================
+# PyInventory shared functions
+#=================================================
+
+setup_venv() {
+    ynh_script_progression --message="Setup Python virtualenv..." --weight=15
+
+    # Always recreate everything fresh with current python version
+    ynh_secure_remove "${final_path}/venv"
+
+    python3 -m venv --without-pip "${final_path}/venv"
+
+    cp ../conf/requirements.txt "$final_path/requirements.txt"
+    chown -R "$app:" "$final_path"
+    (
+        # Activate venv in sub shell
+        set +o nounset
+        source "${final_path}/venv/bin/activate"
+        set -o nounset
+        ynh_exec_as $app $final_path/venv/bin/python3 -m ensurepip
+        ynh_exec_as $app $final_path/venv/bin/pip3 install --upgrade wheel pip
+        ynh_exec_as $app $final_path/venv/bin/pip3 install --no-deps -r "$final_path/requirements.txt"
+    )
+}
+
 #=================================================
 # Redis HELPERS
 #=================================================
diff --git a/scripts/change_url b/scripts/change_url
index 2b32057..872af64 100644
--- a/scripts/change_url
+++ b/scripts/change_url
@@ -38,7 +38,7 @@ redis_db=$(ynh_app_setting_get --app="$app" --key=redis_db)
 #=================================================
 # BACKUP BEFORE UPGRADE THEN ACTIVE TRAP
 #=================================================
-ynh_script_progression --message="Backing up the app before changing its URL (may take a while)..." --weight=40
+ynh_script_progression --message="Backing up the app before changing its URL (may take a while)..." --weight=15
 
 # Backup the current version of the app
 ynh_backup_before_upgrade
diff --git a/scripts/install b/scripts/install
index 5f2aede..ac5e51d 100755
--- a/scripts/install
+++ b/scripts/install
@@ -63,7 +63,7 @@ redis_db=$(ynh_redis_get_free_db)
 #=================================================
 # INSTALL DEPENDENCIES
 #=================================================
-ynh_script_progression --message="Installing dependencies..." --weight=40
+ynh_script_progression --message="Installing dependencies..." --weight=10
 
 ynh_exec_warn_less ynh_install_app_dependencies "$pkg_dependencies"
 
@@ -101,20 +101,7 @@ ynh_system_user_create --username="$app" --home_dir="$final_path" --use_shell
 #=================================================
 # PIP INSTALLATION
 #=================================================
-ynh_script_progression --message="Install project via pip..." --weight=80
-
-python3 -m venv "${final_path}/venv"
-cp ../conf/requirements.txt "$final_path/requirements.txt"
-chown -R "$app:" "$final_path"
-
-#run source in a 'sub shell'
-(
-	set +o nounset
-	source "${final_path}/venv/bin/activate"
-	set -o nounset
-	ynh_exec_as $app $final_path/venv/bin/pip install --upgrade wheel pip
-	ynh_exec_as $app $final_path/venv/bin/pip install --no-deps -r "$final_path/requirements.txt"
-)
+setup_venv  # function defined in _common.sh
 
 #=================================================
 # copy config files
diff --git a/scripts/restore b/scripts/restore
index e4cbdfb..4cdd9a1 100755
--- a/scripts/restore
+++ b/scripts/restore
@@ -78,7 +78,7 @@ chown -R "$app:" "$final_path"
 #=================================================
 # REINSTALL DEPENDENCIES
 #=================================================
-ynh_script_progression --message="Reinstalling dependencies..." --weight=40
+ynh_script_progression --message="Reinstalling dependencies..." --weight=10
 
 ynh_exec_warn_less ynh_install_app_dependencies "$pkg_dependencies"
 
@@ -86,18 +86,7 @@ ynh_exec_warn_less ynh_install_app_dependencies "$pkg_dependencies"
 # REINSTALL PYTHON VIRTUALENV
 # Maybe the backup contains a other Python version
 #=================================================
-ynh_script_progression --message="Upgrade Python virtualenv..." --weight=10
-
-python3 -m venv --upgrade "${final_path}/venv"
-
-#run source in a 'sub shell'
-(
-	set +o nounset
-	source "${final_path}/venv/bin/activate"
-	set -o nounset
-	ynh_exec_as $app $final_path/venv/bin/pip install --upgrade wheel pip
-	ynh_exec_as $app $final_path/venv/bin/pip install --no-deps -r "$final_path/requirements.txt"
-)
+setup_venv  # function defined in _common.sh
 
 #=================================================
 # RESTORE THE PostgreSQL DATABASE
diff --git a/scripts/upgrade b/scripts/upgrade
index 5d21061..f8eedaa 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -29,7 +29,7 @@ redis_db=$(ynh_app_setting_get --app="$app" --key=redis_db)
 #=================================================
 # BACKUP BEFORE UPGRADE THEN ACTIVE TRAP
 #=================================================
-ynh_script_progression --message="Backing up the app before upgrading (may take a while)..." --weight=40
+ynh_script_progression --message="Backing up the app before upgrading (may take a while)..." --weight=15
 
 # Backup the current version of the app
 ynh_backup_before_upgrade
@@ -85,20 +85,7 @@ ynh_add_systemd_config --service="$app" --template="pyinventory.service"
 #=================================================
 # UPGRADE VENV
 #=================================================
-ynh_script_progression --message="Upgrade project via pip..." --weight=80
-
-python3 -m venv --upgrade "${final_path}/venv"
-cp ../conf/requirements.txt "$final_path/requirements.txt"
-chown -R "$app:" "$final_path"
-
-#run source in a 'sub shell'
-(
-	set +o nounset
-	source "${final_path}/venv/bin/activate"
-	set -o nounset
-	ynh_exec_as $app $final_path/venv/bin/pip install --upgrade wheel pip
-	ynh_exec_as $app $final_path/venv/bin/pip install --no-deps -r "$final_path/requirements.txt"
-)
+setup_venv  # function defined in _common.sh
 
 #=================================================
 # copy config files