If you want to do recurring payments, gateways will give you a transaction ID you can store instead of the CC number. Then, when you want the next payment, you

If you want to do recurring payments, gateways will give you a transaction ID you can store instead of the CC number. Then, when you want the next payment, you give them the ID and ask for more money. You don't have to store the details at all, but you can do everything through your site without handing the user off to a third party.