There's so much babysitting required. I've managed to wean all but one of my clients off self-hosted email. They are paranoid and insist on keeping it in-house

There's so much babysitting required. I've managed to wean all but one of my clients off self-hosted email. They are paranoid and insist on keeping it in-house. It's such a big time suck to deal with spam filter tuning and blacklist removal requests and the like, but they keep paying the hourly rates for it.