Same here I never take an up front payment on a first clean and can't say I have ever got
stung.
I find messers usually act up after the second or third clean when the novelty has worn off.
Its up to the individual if they want to charge extra on a first clean, I never did as I considered every
first clean a gateway to more work.
When starting out your trying to win work and not trying to cash in, this can come later when you've
build a successful business.
Different if they are looking a one off then I would always charge extra.