This has to be an answer that is up to each individual. I watch a pro like Bencb ,he plays 20+ tables at highest buy-in Mtt's on a Sunday and it blows my mind. How can he make decisions for this amount of money, even if it is the early stage of MTT, usually as he gets near the end of his 12 hour streams he is down to a more manageable number. I could never do this, for myself I can start with 6 at most, and if I get to the money, I hope I only have 2 or 3 at max.