Removing the old chain drive garage door opener and installing this new belt drive one took about 2-2.5 hours, and involved a lot of grease and dirt. But it was not too difficult since I was able to reuse the existing ceiling mount attachments, the garage door attachment, and the opener wiring. I did have to add the safety sensors, and they are sitting on the floor in their correct positions, but I was not able to mount them because I have no concrete drills or screws. They should be fine unmounted.

This new unit is actually nicer than the old one because it has a rolling code, the lights can be turned on without opening the garage door, and there's an external keypad. However, I am worried about how much stress the heavy single-piece garage door puts on the motor, as this old door is heavier than modern sectional garage doors, and does not move along a track.