True and a fair point. Not really the same point though, I wasn't suggesting 'whenever' payment terms.
I just think it's unusual for any business to force payment methods on their customers. Maybe it's not? I can't think of any other single example (other than cash for the tax dodgers).
Car hire companies force you to use a credit card these days.
Plenty of local shops only accept cash.
Plenty of online shops only accept PayPal.
But even if that were not the case, there’s nothing wrong (in my opinion) on insisting that customers pay by direct debit.
The householder doesn’t have to be a customer if they don’t like it.
For me personally, I don’t have a problem with payers, they all pay within a few days. But if it became an issue, I’d have no hesitation saying “pay by direct debit or find another window cleaner”