Good question - and I agree that simply "memorizing" and "regurgitating" the problem is not that useful in the end because, of course, these aren't the exact problems you'll see on the exam.
Also, if you do something pretty much immediately after youv'e already done it (same day, next day, etc), then you're likely to remember it even if you haven't internalized the learning and solidified it in your long-term memory. So that's not super-userful either.
What I would do instead is this: you might actually do a question (fully) 2 or 3 times over some period of time - maybe twice right in a row, because you messed up or you want to try to find a different solution method or try the official solution method or whatever, and then maybe again at some later date (a week or two later, when you've partially forgotten it).
But you might also want to "re-analyze" questions too. So maybe I study this one problem today and I really pick it apart and figure out: what are they asking, how do I know that, how will I recognize something similar in future, what's the best approach, how do I know that, what's an alternate approach if I get stuck, how can I make a guess, etc?
In a week, I might look at the problem again and see (without actually doing it) whether I can still answer all of those questions. If I can, then I've learned to recognize a problem like this, and I don't necessarily need to try it again right now (though I still might at a later date). If I *can't* answer all of those questions, then I know that I did NOT internalize all of my learning from before, so I *do* need to try this one again, go through the analysis again, etc.
I just got to this sentence in your post:
I seem to understand the concepts within the context of the problem, but if I attempt a new problem with the same concepts, the investment I put in does not always pay off.
Do you have an idea now, from what I wrote above. what the issue might be? The way in which you're going about seems to be more focused on memorizing *this* problem as opposed to internalizing lessons that could be used on different-but-similar problems in future.
Read the How to Learn section here:
http://www.manhattangmat.com/blog/index ... an-part-2/Let me know what you think.