How long should one wait between bowls?
That's up to you, right?
Personally, I have smoked about 3-5 bowls for most days on average for the last 35 years or so.
Sometimes none, if the wife and I are on a road trip which we love to do.
But on a typical day that means one in the morning with the morning coffee then one at some point in the early afternoon, usually after lunch, and one right after dinner. Those are the minimum and the must-have-pipes for me. Throw in a couple more in between and it's been a good day.