Just to be clear, I'm not suggesting that people stretch or distort their trading plans completely and run away by taking entry points, exit points or patterns at increasing distance from what is consistent with their original trading plans. To do that would defeat the whole purpose of a trading plan. NO - I'm saying that a limited degree of flexibility needs to be built and hard-wired into trading plans - and that should be at acceptable levels of risk.
Every set of rules traders come to, evolves from a primary need to manage their personal psychology. Evidence would have been evaluated not just about chart patterns but about one's patterns of interacting with them, in coming to any set of rules or plans that work. The rules and plans come about for a purpose or purposes - obviously.
Markets evolve too; changing subtly in various ways. It's not me who said that. Zanger, O'Reilly and some of the other 'greats' said it. I'm speaking generally. Some may feel a need to respond with the usual 'for me'. My statement here is not meant to change anybody's individual trading plans, rules or methods. So others remain free to do what they wish.
I observe that when one is on the path to shaping one's personal trading rules to achieving profitability, one is more receptive to 'evidence'. Once consistent profitability comes, there is not that great a 'need' to do more. But that does not mean people will not do more. As many a seasoned trader will say (WTTE), 'Repeat the plan - plan your trade - trade your plan'. So I support entirely what Alexander is saying. But I'm saying about something a bit different, but related.
My personal strategy which is different from traditional concepts of 'method' or 'trading plan' includes a clause to remain receptive to new evidence and changes in the markets or myself. Strategy includes sub-strategies and methods. In this http://bit.ly/1XoNOJs I've separated various concepts and put them back together. So, my personal trading strategy would have a clause that says, 'Remain vigilant and flexible to changes in markets and myself. Use any method that may enhance profitability and achieves it. Make changes where appropriate, once consistent with grand mission and grand strategy.' That's not meant to be a prescription for others. It means that sub-strategies and methods may change, if based on sound evidence.
For the avoidance of doubt or 'for me' assertions, I really have no wish to change anyone's trading plans. I only mention the above because I think it may help unknown others to evolve further.
No one suggested 'change himself'. If flexibility of mind means changing one's self, then it's for each to decide for themselves what to do (or not).
Brainless trading is for the brainless and those who postulate it, to educate us all about. Thankfully I know I have a brain, although I've never seen it. I also believe I have two kidneys, even though I've not seen them. Who knows - maybe there are brainless or brain dead corpses actively trading and making big money. I just that I don't know it. ;) :)