Picked up a nursery the other week, priced it at £120 monthly, £150 2 monthly and the first clean at £300 because they're old leaded windows with stains all over them.
The owner gets chatting to me when I turn up to do the clean and it turns out he recognises me from the gym we go to. Have a good old chat and we talk future frequency of cleaning.
He says, well seeing as they've not been cleaned in around eight years I don't think we'll need it too often. Would every 6 months @ £300 be ok with you. Needless to say I walked away from there grinning like a Cheshire Cat