I sell all of my old systems and nearly all games. I see no reason to keep them, once they get to a point where I know I won't play them again.
For many years, maybe 2000 through 2014, I spent next to nothing gaming, though I played fairly regularly. I never bought games anywhere near launch, so I was generally spending less than $20 per game. Then, as soon as I was done with a game, I resold it. The only exceptions were Halo games, which I usually bought at launch. I estimate that my net gaming expenses were about $100 per year, excluding an occasional console purchase.
In 2014, with the release of Mario Kart 8, and the replayability of that game, I broke my "rule". I purchased it at launch, and never resold it (I still play it occasionally). Then I purchased Destiny at launch, and never resold it. So, I threw out my rule book. I still sell most games when I'm done with them. But, since I buy more games at or near launch, I lose a lot more money on them. I'm probably spending $300 to $400 net annually on games these days.