I'd only regret it if I didn't use it.
I owned several firearms once, when I got married I didn't go shooting so much so I sold them.
Made out OK.
Like above, just chalked any losses up to a 5yr rental!!
I don't buy high-end instruments, but any time I make the decision to liquidate any type of gear/tool/auto, I run an ad hoc algorithm in my head to factor what I paid vs what I want for it/holding costs and whether I can amortize the difference as a decent cost of ownership.