By the way, I don't have a clear direction as to whether to approach all cards as a hobby or as an investment. I may consider some cards as only a hobby, other cards as only an investment, and other cards as both a hobby and an investment. I'm not really sure at this time.
As far as penny sleaves vs top loaders vs one touch vs graded slabs, are you still not using value or price as a determining factor? Which, in turn translates to how well you intend to protect them? I mean, even as a hobby, do you still not use an "investment mentality" by saying that this card belongs in a penny sleeve, but that card over there belongs in a one touch?
Unless you treat all cards the same, regardless of condition, regardless of scarcity or popularity, it seems to me that even hobbiests are using an investment mentality when they instinctively choose how to protect their cards.