We send our reminders to renew 30 days, 14 days and 7 days in advance, and a last reminder 3 days before the expiration date.
This is because some merchants are on vacation during three weeks. This way, their shop is not accidentally switched back to the free version.
If you pay your first upgrade for one month, then you will get an e-mail the next day with instructions for extending your shop. Don't worry, you have enough time. The shop and the included domain name remain active until the expiry date.
Do not extend your shop on the last day! It's possible that your payment is received by us later, for example when paying by bank transfer. Your shop gets extended on the expiration date, so you will never pay too much by doing an early renewal.