EDIT: I should've clarified that I don't spend a WHOLE Sat for a car oil change. But for a 30min work on the car, you have to go there, wait to drop off car, listen to dealership clerk going on and on about expensive 'preventive' repair I should get (any my family friend mechanic tells me none needed), wait a few hours (because of other customers at same dealership), and get a ride back dealership to pick up the car. That's like 2-5hrs.

As for going to non-dealer mechanic, well it is hard to find a good mechanic you can really trust. And such mechanics are usually booked.

On my very 1st car last oil change, I got an oil change at a shop I hadn't gone to before, for lack of time. Later I learned the mechanic had jammed the cap to the bottom of the motor oil tank at an odd angle and had just jammed it on, destroying the thread on the tank. One more oil change and it would've meant having to replace the motor oil tank.