The article basically talks about how people react too quickly to change and try to change things to counteract that change and that causes further problems. That's exactly what I've done with my portfolio - whether it's dropping services too quickly that became profitable (Prosystems Daily Bargain being an example last year) or changing stakes at the wrong times before a drop in performance (Mr Gekko and Systematic Betting recent stake increases). But the other side of the coin is that some changes I've made have rebalanced my portfolio for the better. So change isn't necessarily bad but I generally agree with the principles of the article - if things aren't going well then don't automatically start tweaking and changing services or dropping them automatically. It's worth waiting and taking time before re-evaluating.
This rule absolutely applies at the moment to Systematic Betting who are having a terrible run -in the last 7 days the service has dropped 47 points and April I'm down 40 points in total - pretty bad timing for me increasing my stake to £15 per bet!! Now it would be easy for me to panic and drop my stakes again but the sensible thing to do, based on past evidence, is to do nothing and ride it out. Looking at Systematic website there are stats that show this has happened before. One month dropping 39 points followed by +86.3 points the following month or a 3 month drop of 72 points followed by a long winning run that added 462 points!!
So for this I'm doing nothing and riding out the run (7 out of 7 losers today was painful though)!