As the contractor says. A good painter can make a bad carpenter look good, and a bad painter can make a great carpenter look bad.
Sand, fill, prep, sand, prime.
Sand, fill, prep, paint.
Sand, fill, prep, paint.
The time to do all that properly one never wants to do it again.
Don't feel bad I only have another 6 rooms to paint, plus the trim painting (baseboards, 15 windows and door casings, 10 doors 9-12 pieces of wood/trim were used for each window and door).
I can see where this winter is going to be spent doing.