Now, of course, you get to settle on your maximum account level at which everything you make over that is taken out and funneled into other accounts. Which is how I'm planning on doing it. I have an account cap and will try to keep it at a level based on what I'm trading. If I ever got to the point where I was trading futures, I'd probably need a bigger account. But for stocks, a smaller account will suffice.
Liquidity can be a problem come tax time.
That can be a problem too. Obviously you really need to learn how to manage your money and to have contingency plans. I like having this control over my finances, personally. You see those annoying Mass Mutual commercials on TV with the smug old dad guy from Frasier saying how non-plussed he is about his money. What a load of bunk, at least from a trader's point of view.