I'm seeking to know if having a personal trading strategy has been able to enhance your trading profitablity ?
Having your personal strategy is good because you are sure of the factors that lead to that strategy being formulated. If you are used to using other people's strategy, you will be riding mostly on trust and not certainty. This does not mean that you should completely ignore hearing other people's strategy, you can listen and learn, maybe even from listening you will have tips to make your strategy better.
... and if you really keep to a particular strategy that worked for you even when it seems it's failing you later on and for how long do you stick to this strategy?
I become uncomfortable whenever my strategy fails like three time in a row. I pause and find out what is is wrong before I continue trading.