I tend to hold onto unneeded things until they either become needed by me/mine, or I can find a suitable home. Unused tie and dress shoes went to a friend for an interview because he didn't have suitable items. No tie and trainers don't get it for interviews. He got the job and I told him to keep the stuff.
Lost a suit that way. It was intended as a loan but never made it back. He wore it to a funeral and then moved. Never heard from him again. I wish I had it back. Wasn't very expensive, about $400 in 90s dollars but still ...
I used to give camping gear to the Boy Scouts but the local pack changed. Really pushed the anti-gay/religious thing, kicked a couple of boys out, and started being run by a team of evangelicals that changed the tone. All the heathens, the kids with personality, and most of the fun, left with the old scoutmaster.
A decade ago there was a local group of campers that would sponsor inner-city kids and take them out camping. Often to the springs in the summer and sometimes as part of an effort to maintain trails. I gave a lot of stuff to that organization. I'm not sure what happened to them. I suspect the three main guys who started it got old and busy with family and the organization went dormant.
I don't tend to sell old gear. Selling puts the emphasis on money and I wouldn't likely get enough to make it seem worth it. Finding someone who can use it, a good home, feels more gratifying, but it has to be the right people.
Over time this is becoming less of an issue. Back in the day I used to buy a lot of gear, follow trends, keep buying things that are a little better. Now, I just don't see the differences and as I've gone to shorter trips and survival use where a lot of the finer points get lost. Hiking the length of the AT with a cheap backpack is going to be painful. But on an easy overnight trip a pillow case and a length of clothesline will do quite well enough. Once I get a rig that works I tend to stick with it so the volumes of stuff I have to give away has dwindled.