I'm going to being contrarian, as is my bit.
I self-host everything and fully believe everyone else should too.
HOWEVER, if your self hosted shit breaks for say, 3 days, how much money is this going to cost you?
For business stuff you really really should determine what your backup plan for 'Oops shit's dead' is well before shit's dead, and honestly, in some cases, maybe it makes more sense not to host everything and have a couple of things that would wreck your business provided by a SaaS company that has a SLA, and on-call engineers, and all that good shit.
Just a thought to keep in mind, I suppose.