yes some we do, my mothers is large 5 bedroom, 4 large windows in kitchen 8' x 4' each , 3 lounges, inc 5 patio windows, but windows upstairs are small, takes less than 15 minutes with backpack, so 4 an hour and you have got £40, my son is happy with £30 an hour, because of WFP, you are able to massivly undercut the trad guys, and make money, without being undercut yourself, its a business plan that works for us and him, and we are in business, a fact that some forget
idealrob
This is where alot go wrong, you should price taking in all problems.
What if you could not use wfp, for any reason(stolen, drought order banning it, RSI in shoulders or neck) you would be in trouble.
Doing a six floor building the wfp can't clean it properly and you have to hire a cherry picker or scaffold tower, you would be out of pocket.
It is very rare to get it that wrong and on domestic you could get away with it, but if you ever go for high and large commercial it could cost big time if you don't forsee a problem you could get.