People have lot of misconception on mechanical trading and compounding, let me first present my understanding on rule based trading ....core of it is........... backtesting, for intra it should be atleast 5 years and for swing/positional entire cycle (10 Years and more ), expectancy ratio is just half way mark, we need to do stree test ,after keeping in mind the luck factor..if you cross this point next comes compounding..if you don't know above terms , learn them ..i have discussed all of this already and go through books i suggested