I have the theoretical knowledge to make decisions on cards as "an investment", but not the discipline. Sometimes I know which cards I shouldn't buy, but I want them now, dammit.
Just as "buy low, sell high" is also a smart approach with cards, I seemingly don't have the patience for that either. Whenever I even need to move cards just to pay for something new I just couldn't resist, I seem to have a lousy track record at selling at the high end of the market.
I have 2 daughters, one who is into baseball right now and the other not so much. My cards (whatever is left, anyway) will go to them and they can treasure them as I would or dispose of them as they please as circumstances dictate...