Your example sounds fair for both you & customer to go to site & prep & basically repaint with higher end traditional materials & a spray job. When talking home painting stuff, a homeowner could pick for a large number of half ass people that call themselves painters to come out & brush cheap latex paint on top of a worn finish for much cheaper, but $250 is fair to them for a FINISHER to do a better job.
When talking just the door panels only you are open to using all sorts of higher end finishes, but when talking painted door frames that are likely wood, painted wood trim with caulk seams & nailholes filled with spackle or caulk, then at least that portion is a traditional homepainting job where skilled use of a good paint brush in either latex or oil base may be more feasible than spraying. I've seen your better [brush] painters in my area charge around 250 to 500 for a quality repaint.
Just started a custom job today with a communicating door unit (inside & outside door in 1 frame) with sidelites in new frames & re-using the historical fluted trim inside & out. Staining both sides of outer door, outside of inner door & everything else gets customer's choice of SW designer white paint. For the stained parts, this is going to be my 2nd spi clear door job. The panels & frames requiring paint, I'm spraying with sw quick dry primer & paint. Then the sucky part for me is brush repainting the old trim & new caulk after installing everything else I've done. This is a good example of what I mean by variables. Basically 3 types of painting in 1job. Since I have to repaint old house trim, it limited me on what I could have used on the new wood door parts to match.
Another sidenote to your example, Any fiberglass door I've ever seen from a manufacturer not prefinished is a raw smc type fiberglass, which would take a hell of a long time to chaulk. Steel doors usually come with a primer which may look nice enough for homeowner to not paint & chaulk later. Just sayin??? Been in door business 27 years in florida, but your area may have something different than I've seen.
Have a SW account at work, but haven't heard of the snap dry before. If you use it , let me know what you think.
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