I second Jason’s “well put” 
I had a hard lesson when it comes to taking a loss when selling/buying cards. The whole scenario definitely gave me more of an appreciation for my collection. Unless you are a seller who knows what they are doing…stay away from “investing” in these cards 
Collect for the fun of it.
just collect for fun or certain cards you love or a certain pokemon.there are many fans who just collect cards like pikachu’s mew’s and other pokemon.now as for investing into cards its more of a half half situation newer cards are worth good profits during the prerelease days but after the set comes out it starts to die down more but cards that are sought after gain some good cash but do remember after a few years they get rotated and tend to get alot more cheaper.sometimes u just have to take a loss into things and just learn from that mistake you made.
I’ve been trying to do this a bit too much. Now I’ve decided to stop it almoust completely and therefore my next years goal / New Year’s resolution is to get rid of all extra and useless cards. This will be an interesting journey since I can finally see how I managed profit-wise.
Buying, selling, collecting…it’s all fun. If you’re in it for the long haul, and take everything into consideration, then you’ll certainly come out ahead:)
I collect for the fun of it, but I sell duplicates to fund the hobby. I hope that one day with poketuber earnings I can break ahead, but that will be years away if that ever happens.
Personally, no, I do it out of pleasure and the thrill of finding a rare card for the collection. 