With a customer's card saved to their account, PostalPoint can renew their mailbox automatically before it expires. Turn it on and set the schedule in Settings → Receiving → Automatic Mailbox Renewal. Saved cards work with the built-in Stripe and Square card processors.
Each renewal emails the customer a receipt. You'll get an email report of any problems, most often an expired or declined card. Those boxes aren't renewed; contact the customer, update their card, and renew at the register. To process renewals immediately instead of waiting for the schedule, use Settings → Advanced → Run Mailbox Autorenewals.
To encourage customers to sign up, create a discounted rate and select it as their renewal rate.
Selecting Autorenewal Rate
A mailbox won't autorenew unless the customer has a card on file and the mailbox has an autorenew option selected.
To select one, click the mailbox number in the Mailbox Manager (Mailboxes) screen, then click the Add Time button. In the popup, click Autorenewal and choose an option.