Yes! I have a similar problem where I look at my collection and notice some games, consoles, computers, and other things that I really enjoy owning but don't use often, and I proceed to sell them... only to regret it not even a month later. I've come up with a system of identifying what I actually care about:
Look at your collection and identify the games, consoles, etc. that you find yourself not using very often.
Take them out of your collection room, off your shelf, whatever; the idea is to separate them from the rest of your collection.
Continue to play your games as normal for about a month.
If you notice yourself wanting to use those things enough to go and dig out of wherever you put them, chances are you're going to regret selling it. If not, sell that stuff.
This usually works pretty well, but since I mostly collect vintage computers and their games, there are often machines that I don't use all that often but are extremely convenient to have when I do need them. Eg. I have an Apple Macintosh SE/30 and Macintosh Plus, and I mainly only use the SE/30 for its ability to read 1.4MB floppies. I can write a Mac 1.4MB floppy using an old Windows XP PC and use the SE/30 to read it, then write those files to an 800K disk that the Plus can read. The SE/30 can read and write 400K, 800K, and 1.4MB disks, but the Plus can only handle 400/800K, and you can't write those from a PC. It would be pretty much impossible for me to transfer data via floppy to the Plus without the SE/30 unless I buy a KryoFlux, which is significantly less fun to use. So I'm stuck in a situation of owning something that I could easily get a few hundred bucks for just because I need it once a month.