The usual problem in self study (of any subject) is that you go towards what is easily accessible from where you are right now, which means you might miss out on useful avenues visible to someone who already has a good view of that "lay of the land", so to speak. You may also lack the discipline to push through something that is difficult for you when you can't see they payoff - an outside influence could convince you it will be worthwhile. Depending on the type of student you are, you can also spend too much time inefficiently on things that are comfortable.
You can try and do something like recapitulate the core curriculum of a math degree, say, but there are constraints there you aren't aware of and it won't be the right path for everyone.
method 2 expanded to "actually ask questions at some of these locations" is actually a good way to inject some outside direction. So it's a mitigation for this problem.
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The usual problem in self study (of any subject) is that you go towards what is easily accessible from where you are right now, which means you might miss out on useful avenues visible to someone who already has a good view of that "lay of the land", so to speak. You may also lack the discipline to push through something that is difficult for you when you can't see they payoff - an outside influence could convince you it will be worthwhile. Depending on the type of student you are, you can also spend too much time inefficiently on things that are comfortable.
You can try and do something like recapitulate the core curriculum of a math degree, say, but there are constraints there you aren't aware of and it won't be the right path for everyone.
method 2 expanded to "actually ask questions at some of these locations" is actually a good way to inject some outside direction. So it's a mitigation for this problem.