Here is my take on things,
If you understand why you are entering a trade, you'll know when to exit it. (leaving aside any individual neurotic human behaviour, technological interferences )
This pondering seems to crop up all the time and to help a trader get to a point from which to progress I would ask them this,
Do you believe the markets are random or not , or are you not really bothered in knowing that ?
I say this because once a person is aware of his natural internal driver in pursuit of knowledge of his/her subject in focus, then it may help in them being suited to developing a particular fundamental strategy with fits their personality looking outwards at the subject matter.
I also think if a person is not aware of this, then I wouldn't be surprised to see erratic emotional driven decisions surfacing, as the internals actions of an individual have no solid belief foundation on how to manage the external fluid actions that the market will continually throw your way.
So personally I would want to get this awareness set at the earliest opportunity within the individual. And yes, it may often be that the trader says, "Hey , I just don't know the answer to that yet." And at that point, I would advise that they need to find it (the answer) before they can expect to make solid progress based on understanding that their internals now are ( at least )aware and are therefore more comfortable and expectant, of how to manage the external market incoming.
I'll call it the "Matching Principle" .
I mean its all about how you cook your beans. Some people will use a microwave, slam them in nuke the hell out of them, hot over cooked beans here stirred in with luke warm beans there, hey that's cooked beans right ?
Well for them yes, maybe their internals are happy with that,maybe they are not aware of any other way, but I couldn't cook my beans that way, nor do I , as I understand it impairs the beans performance, so my internals drive me to cook the beans in suitable sized pan over a steady controllable flame, gradually heating the beans evenly .
That's how I must cook my beans , understanding the ingredients and the energy forces applied to them, and how the beans are likely to react in that environment !
If you want to understand the market and trading, first understand beans and baking them.
Just my beans into the pot.