There is an interesting dichotomy, IME your available time definitely goes down drastically. That said, I find I actually get more stuff done (stuff that matter

There is an interesting dichotomy, IME your available time definitely goes down drastically. That said, I find I actually get more stuff done (stuff that matters anyway), because you get brutal about cutting off distractions. For example, I'm now training for a half marathon and learning a new programming language while parenting two small children. I never achieved such things while childless. Similar with work, I used to be a long hours worker, I now get, hmm, 90% of the work done in 75% of the time. So, yes you'll have less time, it will be tough in many ways, but that doesn't necessarily mean it will suck left right and centre. It will be different.