Both sides of the coin here. I often don't regret moving on from instruments. Usually, if I've made the decision to sell, I've thought it through enough before hand that I'm beyond any doubts. I think in the 22 years I've been playing there is maybe one bass I still think about, and that's out of probably over 100 I've owned, but it's a type of bass I could get back if I wanted. The flip side of it is I own what I consider three sentimentally valuable instruments. The first is a 1989 Fender longhorn Jazz that was originally my father's as he dabbled a bit in bass when he was younger. The bass is has a pretty big flaw in that the truss rod nut is stripped pretty bad and it's not something that's easily replaceable, so neck adjustments aren't the easiest. It's also got some high frets and some dead spots, but even with the flaws, it's never going anywhere. That said, I'll probably get a new neck for it at some point to make it more playable. The second is a 1993 music man sterling. It's quite worn, is finished in the most uninspiring looking red, but I acquired it at 16 and it's been through a lot with me. It's also the first year the model was produced, so again, it stays. The final is a Fodera Monarch "New Standard" I got around when I graduated from grad school, so it's an important milestone instrument so it will be staying with me.