What kind of mess can I expect when the job is done?

​Very minimal to none. I cover everything with a layer of polyethylene plastic, sealing up any gaps and seams, using thorough techniques I've acquired over the years. When it's time to clean up, I do so in a manner that allows any falling mud or dust to be caught by the plastic on the floor, and roll everything up into a bundle once all is said and done. When all the garbage is out, I will go around with a damp cloth to get any minimal overspray. The idea is to always try to leave the job looking like I was never there, with the only difference being a new ceiling.