How long is a Piece of String?
It really doesn't matter how much a Player has, because someone playing a 1% Bankroll Strategy is in a perfect position with $100, buying in to $1 Games. It really is dependant on your Buy-ins and Bankroll, A player using a 2% strategy would be able to buy-in to the same level of Games with only $50, So it is down to each individual player what he feels Comfortable buying in with, as opposed to how much he has in his Account.
Personally I have over $600 in my Account and I still buy-in for $1, Because I don't play Poker to win Money, I play purely for the thrill of the chase, and the Fun of it, If I am not having Fun and enjoying the Game I will Log off, and find something better to do.
Some might say I am wasting my time because I could buy-in for more and win more, But I say "It's my time to waste, and if I went to the Cinema or a Football game, it would cost me a damned sight more and I wouldn't get more money for sitting there" To me watching 22 men kicking a ball around for 90 minutes is a bigger Waste of Time.