I made the HUGE mistake of hiring Certa Pro to do several interior rooms of my house, and remove popcorn ceiling in a bathroom. What a nightmare! They didn't paint any door jams, they broke a cedar window sill-and didn't bother telling me, they gouged a hardwood floor, they never sealed the room that had the popcorn removed--causing white powder to be in all rooms of a 2 story home. I can go on and on. Horrible company
Maybe you've just moved into a new home, and you haven't got around to buying brushes and rollers yet. Perhaps you're worried that your brush-skills aren't that good, and you won't achieve that professional-looking finish that you’re really going for. Handy professionals will turn up with everything they need to get the job done, from ladders and brushes, to rollers and tarps. You just have to provide the interior paint and primer!