Some contractors work on time and material others on a firm contract. I would never hire the former and am leary of the latter. A contractor may low-ball a bid to get the job planning to make a killing on change orders. If you say good morning to them, they charge you extra for that. If the contract is not very, very specific and extensively fleshed out or if they display their change order schedule prominently on top, show them the door.
Because of our wet/cold weather, another painter was booked out through August as of May 7th, 2016. Anyone even thinking about a VA loan refi should get estimates for painting and pest inspections BEFORE starting on the loan paperwork, otherwise you will have difficulty getting painting and inspections done in a timely manner (and it is my understanding this is common with VA loans.)
If you decide to hire help, have several contractors inspect the job and provide proposals. You'll probably find huge price differences for the same job. A Checkbook undercover shopper got quotes from nine Washington-area contractors to repaint the walls, ceiling and trim for a living room, dining room, family room, bathroom and kitchen. Including paint and supplies, prices ranged from $2,650 or less to more than $6,500.