There are pros and cons. Some self-hosting PROs are that you can add essentially unlimited mailboxes and new domains without paying more in monthly fees. Have a

There are pros and cons. Some self-hosting PROs are that you can add essentially unlimited mailboxes and new domains without paying more in monthly fees. Have a new weekend startup idea? Set up your emails yourself for 0 additional mail hosting $. Another pro: Complete control over everything (which could also be considered a con if you don't want more work). Want to set up a catchall? Want to redirect a single incoming email to multiple recipients? Want to get a copy of all emails sent by one email account for backup? Pretty straightforward. Some CONs are that you will be adding yet another set of admin and monitoring duties, which will be dramatically compounded if you host emails for more than just your own interests (e.g. if you also decide to host email for your friends, family or clients). You'll also need to be pretty fluent in SPF, DKIM and possibly DMARC, although that is something you'd probably need anyway if you are a startup and buying your own domains. You'll also need some security, since mailservers tend to get more brute-force break-in attempts than web servers. At least in my experience. And you'll also need to be on top of blacklist monitoring services and learn how to request blacklist removals. Oh! And you'll need to decide if you want virus checking for suspicious emails and attachments. Oh! And a spam filtering solution! For your specific question, have a backup at all times, even if it's only the barebones mailserver environment itself, so that you can quickly restore to a new box and be back up (although you'll still need to change your DNS settings for all impacted domains and wait for that to propagate) TLDR; If you want complete control and want to pay one price for almost unlimited domains and mailboxes, self-hosting is great, but beware the added workload and headache.