I would never do gloss on walls. Overall I prefer less shine. Flat on ceilings, unless you're doing some really glam reflective treatment; it is less expensive. I use matte for my walls, which not reflective but it is washable. Satin is my choice for trim and interior doors. For outside doors and shutters I use semi-gloss.

That is very high! I have had 3 paint estimates for my entire home, no doors or trim- just walls. 2800 sqft, rambler. The bids were 2200 (no paint included) 5400 (paint and prime included) and then a random bid of 9400, which seems way out of the ballpark.

Thank you decoenthusiaste and SapphireStitch! I cannot thank everyone on this site enough for your feedback and suggestions. This is my first time using the houzz discussion board community, and it has been truly helpful and comforting to hear your advice. Will update some photos once we paint and are moved in, to show how the space has come together. Thanks again everyone :)

Contractors love flat paint because it is cheep and it hides a multitude of drywall finishing flaws. The less time they spend fixing errors the more money in their pockets. No you don't have to repaint, but I would recommend you do with satin paint. It will highlight the drywall flaws so they can fix them while you are still under warranty. Flat paint is not durable enough for trim and doors. The higher the gloss the more durable the paint. I like using semi gloss for trim and doors. Some don't and use a less gloss. Ceilings are usually flat paint, because ceilings arn't subjected to wear. But I would also paint the ceiling satin to highlight the drywall flaws and get them fixed. It is easier to paint while the place is empty.