I have selfhosted email for 10-15 domains for about 20 years (qmail toaster, then mailinabox). I also pay for fastmail.com and purelymail.com so that I have email addresses that still work if my hosting goes down. I host on AWS, and if something goes wrong with my AWS account, I need a way to communicate with AWS that doesn't require servers running in the affected account.
I have selfhosted email for 10-15 domains for about 20 years (qmail toaster, then mailinabox). I also pay for fastmail.com and purelymail.com so that I have email addresses that still work if my hosting goes down. I host on AWS, and if something goes wrong with my AWS account, I need a way to communicate with AWS that doesn't require servers running in the affected account.