That would be a really expensive way to do it and you run the small risk of not getting matching frame styles / sizing. I did one house, back and then front windows but that was only due to other renovation work and trying to live in the house, but even that still cost a fair bit more than I was quoted for all at once.Windows are aging, some are blown, so I was thinking if we're replacing, might be worth just doing the whole lot. Now I'm wondering if doing it window by window may be better, but I suspect that given you end up paying for a full days work, even if it's just half a days job, more might be better regardless...