Hi Fresher,
As you've rightly pointed out, rigid monthly payments (same amount/day every month) don't tend to be practical for window cleaners as things change and stuff happens.
You might do the job late or you might change the price from month to month e.g. if you only do fronts or add on a conservatory clean.
Fortunately GC allows you to bill customers manually on an ad-hoc basis after you've done the work, though it can be a bit tedious figuring out who to bill and manually entering amounts etc.
In case you're interested, the way it works in Cleaner Planner (which integrates with GoCardless) is this:
1. You mark the job as "Done" on the worksheet or "Planner".
2. GoCardless payers end up on your "Debts" tab (just like BACS payers) as they didn't pay on the day.
3. You go to the "Debts" tab and click "Start GoCardless" next to a customer to take payment.
It only takes a couple of seconds to kick off each payment (amount and reference are prefilled) and the debt will automatically come off your list when the payment lands in your account.
The "Start GoCardless" button only appears when the customer is in debt so there's no way you'll bill for work you haven't done yet.
Cheers,
Rob