As a founder-CEO, I think I worked in the office about 50 hours a week on average.
I never left the office at the end of the month or quarter until the last sales rep closed the last deal.
I never left the office during a release until all the final post-release smoke-testing was done and we were in production for 2+ hours.
Beyond that I tried to spend no more than 50 hours in the office on a non-travel week.
It doesn’t matter though.
You will think about how to win, how not to fail, how to fix issues, how to recruit that amazing VP … every waking hour.
It will seep into every nook and cranny of your brain as a founder.