I agree with this whole heartedly. I've acquired some badly damaged cards when buying collections. If it is from the 80s and 90s, if I have another version they have been trashed. These are water damaged, stuck together, badly stained, etc. I have a hard time with the thought of throwing anything else away. Granted, people can do what they wish with their own stuff.
Even damaged cards of stars or certain teams I've given to my sons (7 and 3). I figure it is good for them to have an opportunity to learn to handle cards without me worrying about them getting destroyed. 80s and 90s cards still have a place in my collection. Doesn't matter to me if others view them as worthless. I still buy more from time to time. I have built 1990 sets of Donruss, Topps, and Fleer with my older boy from unopened packs. Still fun for me to open the hideous looking orange 1990 Donruss cards and talk to my kids about the players and my memories of watching them when I was a kid.
It is true that I have way too many extras from some of these sets. One of my goals is to finish sorting my collection and to get rid of some of my extras by offering them free on Craigslist. Ideally they go to some kid interested in starting a collection or to a collector and not to someone that will scavenge and then trash the rest, but how does one know for sure.
As others have said, I don't think trashing cards increases value when there is still a huge supply. These cards will never be "worth much" in terms of making an investment but can certainly fill in holes in someones collection and are can be to someone.
