I find that if I get bored with a game if I don't play it for 4-5 months I'll go back to it and it will be fresh again. There's a reason I bought most of my games and the same reason I keep them.
I've also the last 8-9 years have been tracking how many games I personally play on each (not party play) and if I do want to sell one, it's one I haven't touched for a couple years.... and then I play it again and decide not to sell it. Sometimes you get a dud once you start really playing it and it's not as good as I remembered and those do go, but those are far and few between.
Sometimes I'm convinced to sell it (firepower) and after I shop it for sale, I always play "one last game" - luckily I did or I'd have sold it. Turns out the black on the playfield really hid that it needed to be cleaned and once I did that, it played nice and fast again (I'd thought it just seemed slow compared to the games near it like F-14....)
The spreadsheet revealed several years ago that I had played Catacomb less than 12 times over a 4 year period, and that was probably play testing it before parties, so out it went. Wish I'd saved it so I could have cashed in on the Classic Stern train, where I was WAY ahead of the curve on those. Oh well.
I don't regret selling it, I just regret selling it so cheaply. No desire to reacquire. (Unless I needed it for software mods)