Earlier quoted context omitted.
A metric major fuck ton. If you truly want to be present and have an active role in your child's life, growth, development et al it's going to force your priorities to shuffle around. If your "startup" is still a priority (but not above your child) you aren't going to be in the office from sun up to sun down. Period. You'll have to make up those hours later (when the child is sleeping) however, in months 0-24, that's…
https://news.ycombinator.com/item?id=7779598
I would say I've updated this to state that I am out of the house around 8:30 am now spending even more time with my kids.
I still get up around ~5:30 - 6:00 am, but don't bounce out of the house as early.
Also, my kids are sleeping better now that they are older (and sleeping in) so I need to stay home later to spend quality time with them each morning.