I had someone work for me who would do 1 swipe across the top of the frame no touch the side frames and a quick scrub of the glass....And this is what happened!
After watching him do this i was asking the customers what the results where like
and to start with they where very happy,i was wondering if i was putting to much into cleaning the glass.
Second month i started to notice more cob webs than normal but still the glass was ok.
Third month started going very wrong ,the 1 swipe across the top was not enough.
It was running off onto the glass,so i put a stop to his way of cleaning and thought thats the end of it.
Fourth month ,Getting lots of complants lost 5 and had to put about 2 days worth right.So what was happening ,well he would clean my way when i was about as soon as my back was turned back to his way of cleaning.How do i know ,i sneeked up and cuaght him twice....Sacked !
So i believe that as long as you dont make a habbit of ityou can cut back on effort but not all the time on the same glass and frames.
I normaly go for 4 across top frame 2 maybe 3 on the glass with the side frames getting a quick touch from doing the side of the glass. then finish of with the cill.