About three years ago I decided to start shooting regularly after about a five or six year absence. I would go to the range maybe twice a year, but wasn't up on the latest guns or their values. Nor did I know that Gunbroker nor Armslist even existed. I had spent many years in depression because of my disabilities. It took nearly dying in a house fire to get me going again.
So, I had two 1980's vintage S&W 686's with 4" barrels. I bought mine, then bought my dad one, which became my second when he passed. I decided I wanted a Glock 17 so I did some online searching and found Gunbroker. I found a dealer in ND that would trade one of my 686's for a Brand New Glock 17 and I was tickled. Thought I had gotten a good deal.
After about a year of getting back into shooting I discovered how badly I had traded, even though I ended up with a Gen 3 RTF With Fish Gills (made it hurt less in ,y mind...lol). It got even worse after I decided to sell the second one, figuring I didn't care for all of the recoil associated with a "Magnum" never thinking I would get into reloading nor the fact I could have shot .38 Special loads in it. The second wasn't as bad a deal, as I did trade it for another S&W, a 642 plus I got some cash, and my wife ended up with a very nice carry gun.
I only wish I had another 686 with no dashes no dots, just a plain old 686. I do see one in my future gun purchases. If I could do it all over again, I would never trade them. I have made myself a rule, that should I decide to let one of my guns go, now or in the future, I have to wait one month before I list it for sale. This only applies to guns I have owned for more than four years as well

I also sold a Russian built AK-47 that was a Class 3 firearm. While I made a good profit, I truly wish I had it back. Same goes for a H&K 91 I sold, just before moving to MN. That one helped fund my move.