Rathr than cut and paste various responses, I'll just answer a few.

One poster said two centuries ago people (men?) averaged five feet high.
Acctually it was closer to 5'6.

Then there is the old rule of thumb that the top of the bench should be at your
palms. I'm 5'8 and prefer a bench of around 34" high, at least for planing.

what is really useful is a stout stop, not dogs for holding both ends. It'
smuch faster with only the stop, and after a little practice, it does not need
to be held at both ends.