I'm surprised that 6 hours of session time in a day is unthinkable for anyone. My young dom friends are easily getting that many while on tour. I did as when I was active, whether at my home base or traveling. 6 hours doesn't sound excessive at all to me as far as demand. Being certain to take time off to replenish energy and have time for your personal life is the challenge. But, I a mentioned earlier, there are other factors to take into account. To the OT, I don't find the person's claim far fetched at all.