It is popular opinion sometimes that a trading strategy might no longer be effective if one begins to loose money while trading instead of gaining.
An important question i ask myself whenever i hear about people complaining or simply discussing a series of consecutive looses they have made while trading using a certain strategy is;
HOW MANY CONSECUTIVE LOOSES IN TRADING CAN YOU HANDLE BEFORE YOU ACCEPT THAT YOUR CURRENT TRADING STRATEGY IS BECOMING LESS EFFECTIVE?
I don't think it this way atleast for my trading strategy, number of losing trades, i generally look for a mental break from the trading, I mean if I consecutively having 3 losing trades, I will stop trading because I know I am carrying the emotional baggage of those 3 losing trades with me,a I take a long enough break to remove that baggage before I jump back in again. For checking the effectiveness of my trading strategy I generally look at a longer term scenario like how much is the winning %age in last 50 trades or 100 trades or last market phase. This is how I decide whether it's time to change the trading strategy.