In USA, unless you are getting high perfromance WARRIOR TRAINING from a hard-core TT coach / Drill SGT... then 1 hr straight is the normal thing. The pace of the lesson is slow, coach is rarely pushing the player much... just getting player to relax, understand some things, and practice without much stress.
Some do some multiball in hte lesson, but is starts so agonizingly slow and maybe later builds... some.
A player not in really good condition can easily do one hour TT lesson with 90% of the adult coaches NO PROBLEM.
A player in decent shape taking multiball lessons in a Korean TT club gets a 10 minute warmup, then gets the living dog-crap SMOKED out of them before the end of the last ten minutes. You would NEVER, EVER expect a dude in great physical shape to not even last 10 minutes when the multi-ball training gets intense with all those powerfull hitting combined with explosive cross step footwork back and forth combination multiball drills at a pace that is a tad faster than one normally can handle...
So one has to know what they are getting into.
if it is light duty, like 90% plus of adult coaching in USA, then 1 HR is no problem.