[Reason077]

I haven't seen an option to set a payment limit, but all banks give you the ability to cancel a direct debit authorisation at any time. For that reason alone I'd say it's always better to use direct debit than give a merchant your credit/debit card for subscription services.

In any case, the banks seem to be very good at refunding direct debits in cases where the merchants appear to be abusing them. My ex once noticed after several months that her gym was still charging her even after she'd cancelled - the bank made it very quick and easy to claim back all the extra payments!