Oh, there's several items I'm selling that I regret buying, but in the big scheme of things they were drops in the bucket so I don't lose any sleep over them. Fortunately, most of the gear I'm selling earned its keep many times over but, for whatever reason, doesn't meet my needs any more so it is time to get rid of it. I don't get emotionally attached to gear because it is all just tools of the trade and it doesn't bother me if it sits idle most of the time as long as it works when I need it. Something that a lot of people don't understand is this: "How much something costs to buy is less important than what it earns." And my philosophy has always been that one piece of gear earns enough to pay for its replacement . . . and then that one earns even more to pay for its replacement, and so forth until after awhile you find you've got a bunch of stuff that all earned a nice ROI -- but got replaced by something better before it actually wore out and became worthless.
This list of stuff may seem like a lot of gear, but if everything I'm selling actually sells for exactly what I'm asking for, it would still only represent about 15% of the insured value of the gear I'm still keeping. I'm definitely not retiring -- ust doing some housekeeping to clear off the shelves and make room for new stuff.