I used to self-host my email. I don't any more, for exactly this reason. And of course this applies to every other "just do it yourself!" enthusiast appeal. I actually want to delegate it to someone who does it full time.
Strange example, because self-hosted email has been pretty much setup-and-forget for me. I’ve been hosting my own email for several domains on a $5 VPS for over a decade and it’s largely just hummed along, without needing babysitting. Very rarely, some ISP’s spamblocker gets a little too squirrelly and I have a brief deliverability issue, but those are rare and easy to resolve.
It was Exim on Debian; generally it would chug along fine for months and then incur some sort of regular sysadmin issue that nonetheless needs dealing with. Upgrades. Occasionally, breaking upgrades. Changes to anti-spam rules on other systems causing deliverability issues. ISP mandating IP migration. Earlier in the process it was an actual, physical rackmount server not a VPS, which incurred extra effort a couple of times to replace it.
And the big one: inbound anti-spam.
It's not that issues are frequent, it's just that there's no guarantee they won't be badly timed. There may come a point in your life where (a) you don't have a lot of free time and (b) you badly need a specific email.
I still have the mail domain, I just pay an ISP to handle it for me.
I heard a lot of people saying hosting your own email server was the best way to be considered as spam by every big email provider. I think it's a big issue, but I've never actually tried it.
