Nope you've lost me, Simon
Are you saying that doing a house that hasn't been done for three years will take you almost the same time as a house that hasn't been done for 3 weeks?
Yes...the caveat being it's not a house overlooking a really busy main road. But even then I've done those and can't seriously say it took much longer. Perhaps I'm just bloody good at what I do 
I don't do frames by the way...just a glass cleaning ladder monkey.
That explains it. Thanks.
The reason for no frames is that in and around Putney there isn't too much (if any) in the way of new builds and the vast majority of the houses I clean are late Victorian with pitted concrete sills and in many cases the original frames. The glass is held in with crumbling putty and in lots of cases a good % of the putty is missing...try wiping that over and you'd stand a good chance of pulling out the remaining putty that holds the glass in...I kid you not!
OK there a good few houses that have modern frames...mainly stained/varnished wood (UPVC isn't popular around here) but even these I don't clean as a matter of course. If on the rare occassion I'm asked to then yes of course I'll do it and add extra.