So far, I still havenât heard anyone quote any rules of thumb for how much testing most successful traders feel comfortable with. All of the books I have seen only tell how to trade their method, not how to run sufficient tests to develop your own. I would be glad to know from any successful traders out there how much backtesting you felt comfortable with before you started trading your system. How much for short term swing trades (i.e. buy and hold for 2-3 hours)? How much for longer swing trades(2-4 days)?