Disliked{quote} I use backtesting as a way of very bluntly determining a strategy's technical validity. You make a fair point about those issues, if they are a concern for you then forward testing is a solution.Ignored
If you've got something that (after taking out spread and commission) makes x pips per month, with proper money management, you can make an absolute fortune.
And the difference between a winning strategy and a losing strategy might be a filter where you only place trades when the spread is < 1 pip.