A straight opener swap on a door that already has working track and hardware is a same-visit job - most of the time is spent on the mounting and the sensor wiring, not the unit itself. The door stays operable by hand through most of the install since we're not touching the spring or cable side of the system.
Where it runs longer is on older New Hope garages where the header needs reinforcement or the existing wiring has to be pulled out and replaced rather than reused - not unusual on a door system that's closer to sixty years old than twenty. We'll tell you up front if we hit that during the walk-through before quoting the job, rather than after we've started.
We don't carry every reinforcement bracket size on the truck for every header configuration, so if yours needs a part we don't have on hand, that piece may need a short follow-up visit rather than finishing same day. That's the one limitation worth knowing before you book.