You make sure that if there is going to be a setback, you do not get wiped out. You keep enough reserve because markets do foolish things at times, you know.
If you are too over leveraged you are going to lose everything, even if you might be right in the long term.
Related trading instruments: Nymex Crude Oil Futures, SPDR S&P 500 ETF Trust (SPY), Nasdaq 100 Index Futures, S&P 500 Index Futures;
