Also 20+ years, only very minor issues. The spam situation has gotten much better over that time, too. This topic comes up every so often on HN and I feel like the "never self-host, it's guaranteed to be a disaster, you have to use a centralised provider" crowd are just louder. Self-hosting my mail isn't something I think about much or talk about much. It's so obvious to me that it's worth doing, and it's extremely low effort.
You say that self-hosting a mail server is obvious and extremely low effort, which simply is not true. But ok, let's say that you happen to have a clean IP and no spam or dmarc issues. You still had to choose what to deploy, which is not obvious and actually setup/maintain your server which is not extremely low effort.
