Identify the requirements of the chosen model
An overhead opener and a wall-mounted unit may place equipment in different locations. Ask the installer to specify the power and accessory requirements for the actual product. Existing nearby wiring is not proof that the planned installation is ready.
Assign responsibility for preparatory work
If an outlet or other electrical work needs attention, clarify who will arrange it and when it must be completed. Use qualified professionals for that work. The door installation estimate should distinguish equipment installation from changes to the building’s electrical system.
Review lighting and everyday access
Discuss the selected opener’s lighting and control arrangement together with the garage layout. Keep shelving, stored items and access to equipment in the conversation. The final proposal should make these practical details understandable without leaving the owner to improvise connections.
Your questions
Should I plan to power an opener from an improvised extension lead?
Have a suitable permanent arrangement assessed according to the product requirements. Do not treat an improvised connection as installation readiness.
Does every opener quote include an electrician?
No. Ask explicitly which preparatory work is included and who is responsible for any separate electrical requirements.