You may find that you will get work as a result of people seeing you working on the ladder.
Even though over 95% of my work is pole, I usually have the ladder on top of the van - people associate window cleaners with ladder/bucket, not pole/pump.
I also find that it is sometimes worth arranging to do a new job on a Saturday, ["Then, next time, it will be such and such day"].
On Saturdays, there are people at home who are at work during the week, and you sometimes get a few that way - these are the people that think that there isn't a window cleaner in their street.
Do be prepared for stepping off the ladder, garbed about with scrims, squeegee, applicator, bucket, [on and off the belt], to be greeted with "Are you the window cleaner"!
You will have to think up a witty riposte!
Baldeagle