sugark - direct debits are normally run once a month on a more or less fixed date.
Setting that date is up to the direct debit originator (credit card company in this case), but it typically either specified as something like a given date (the 25th of each month) or a relative date (the last Thursday of each month). This means the actual date can vary by a few days if the 25th for example happens to be a Saturday or if the last Thursday is the 31st one month and the 25th another month, but it will always be within a short range.
Of course, the transaction is just an automated transaction and the originator could - if they wanted to - run direct debits every day. There is no real benefit to them to do this, so this is unlikely to happen.
You can set up a standing order to pay out of your account every month on a fixed date of your choosing, but the amount would be fixed, so that wouldn't really suit in this case.
Best bet is to get into the habit of doing your payments online at a given date each month - that way you can maje sure it goes in at a time that suits you and for the amount that suits you.
z