[SeanK]

Spruce I had the same problem as your friend and got rid of the properties with the problem
window frames.
I must have got about 30% like that when starting up which was too many to go back and clean the bottoms
I would still use the same method as yourself on some of the better paid properties.
Certainly in my area I wouldn't want to be converting a established round to WFP for that reason.
I never put water above vents because you just don't know, one day it could work fine the next it could drip
like mad.
But I do clean above vents using a separate pole with a fixi clamp to which I connect a damp microfiber wrapped
around a sponge.
Takes me about a minute to do along the tops of every window and this also removes cobwebs so no cleaning them
of my brush and glass which saves me a bit of time and water.

[duncan h]

Always do vents. Never had a problem. Just give them a good scrub on first clean,  then a quickie after. My brothers window cleaner misses top frame out and they look poope. Full of muck

[dazmond]

after  4+ years WFP its the best tool for the job most of the time but theres still room for a squeegee on some work.

90% WFP/10% TRAD

i was 100% trad for 17 years before WFP.