Use caution with deleting email accounts. If you delete it, someone else may be able to register it, assuming its a free or paid service and not on your server

Use caution with deleting email accounts. If you delete it, someone else may be able to register it, assuming its a free or paid service and not on your server. This could lead to account take-over for other services you use. Consider instead reducing your account to the minimum required, then reject all inbound messages, or all messages not in your address book.