Depends on access, i had some where it was a nightmare so got shut
BUt got some now only a few hours worth and its some of my best paying work, charge about 7-8 pound , they have one top window one bottom at front , and 2 up 2 down at back, sometimes one or two more
Easy work i love it
I do it trad as well as its quicker than changing as some of the access is over flat roofs, down alleys etc , i can run round it quicker with a ladder