<p>I would never hire a painter who did NOT cover the windows in plastic. If they are trying to cut corners by not covering the windows, they are not going to remove paint splatter when they are finished. I wouldn’t wash the windows before painting because a good painter will caulk around the windows to give you a good seal before painting. some of the caulk may have to be wiped off and this will mar a freshly washed window. Make sure your painter spends a good deal of time prepping-- caulking, filling wall cracks (if applicable), etc., and make sure they do NOT delute your paint with water under any circumstances.</p>