I count the windows and then times by 1.5.
One window to me is counted as two windows that are not big windows if that makes sense. For example a regular patio door size window is 1 window. I always clean the garage doors and again that is counted as 1 window.
Then I look at the price and think about the time it will take and also how difficult the windows are. If it all make adds up then thats the price I quote.
I always quote on the higher side, even from when I started out. I wanted to grow with good value work and not worry too much if I do not get the job.
I normally win 1 in 2.5 quotes. But I do not have any grudge cleans all are priced well and what I want to earn per hour