I use Radicale for my calendars and contacts as basically every program, app or device can handle caldav/carddav.
Self-hosting email however is too painful. Not that it isn’t easy on principle… but because the basics are simple all the big mail providers have developed a lot of ways to automatically filter out all those quickly put up mail servers mainly used to distribute spam. So having your own mail server while also constantly jumping through all the hoops so your mails are actually received is barely worth it.


The money flows from Microsoft to schools and universities to condition them them to think MS is the only option and then from Microsoft to non-tech people in deciding positions as bribes and favours so they decide to pay MS a fortune for shitty SAAS. It’s basically corruption used as an investment.
Oh, you meant that side of the money… Yeah, not expensive at all. There is a reason everybody can get email for free or for very little money if you need advanced functions and active service. And there is a reason the big providers are now basically running with whitelists only, because every idiot and their mom can run their own service. There is a reason why simple office solutions you can also get for free are nowadays –like so many other things– porvided as SAAS: to make money off idiots and paid morons.