If you want to invest, speak with a reputable financial advisor. If you want to collect, get the cues that strike a nerve with you. Either you like the design, history, backstory, colors, etc. If it sparks emotion, buy it. Don't worry what it's worth or what it may be worth in the future. People too often conflate investing and collecting. IMO, they should be kept separate. If you consider your collection an investment, then you may as well sell everything you have & buy a bunch of lottery tickets.
I have a very, very early Thomas Wayne cue in my collection. Regardless of value, it's never leaving my possession. It sparks emotion in me on multiple levels. For me alone it's fascinating, inspiring, vengeful, comical, and historical all in the same. It means something to me. And that's why it's a collectible, not an investment. I don't expect anybody to understand nor do I care. It's my collection, not theirs.