Do you trade and borrow on margin? I don't like to use margin (my account is a margin account though) The whole borrowing thing sounds too risky.
I guess I am the only "No" vote so far. I only trade options and that gives me "leverage" without debt. I am not comfortable with debt of any kind, even for investment.
whether or not to use leverage has an awful lot to do with an instrument's beta/volatility as well as whether you trade one instrument/diversigy, your trading time frame (minutes? hours? days? weeks?), and should also depend on the historical drawdowns your system takes (with a lot of fudge factor thrown in).
1) 7-1. 2) Letting small losses turn into large losses is risky. 3) Don't get too hung up on paying margin interest.