Bath fan, only for a home-owner, and only if its easy. Not for a GC. Once made the mistake of saying I'd do it all, and had an otherwise quiet remote fan turn jet engine due to duct noise. Definate "No" on range hoods, wont even hang them. Extremy rare for me to patch wall openings, and absolutely never paint. The way I see it, its a value to the customer to get someone in to do a proffessional job in their trade, and at rates comparable to the that trade. Although it seems only Plumbers rates are over, or comparable to ours, I'm no plumber by any stretch.
