Tardiness is the main issue, is it?
This one makes me laugh really. In order to keep prices reasonable, it's better practice to have a full workload Spring to Autumn, and allow the gaps between cleans to grow longer in Winter. There's little choice really with shorter daylight hours and down time for freeze ups.
The alternative is to make totally sure you can be on time in Winter, which would mean being very short of work from Spring to Autumn.
Apparently, the first scenario is called 'turning up when you feel like it.'
I once had a customer who complained that the gaps between my visits were too long. He also used to want me to do extra jobs (with no notice) and even wanted me to de-moss his roof (I wouldn't do that). Eventually, he sacked me (it was a relief). Not before I pointed out that if even ten per cent of the customers wanted extra work done (as I did for him), the gaps between cleans would be even longer. I knew I was staying sacked and was fine with that, but he did concede my point.