I don’t truly regret anything I’ve sold because I simply had to.
But I do get quite wistful about my MBL 121 omnis.
I owned them for about 10 years and nothing else sounds like them.
I also Sometimes would like to listen to a pair of waveform Mach MC
Monitors that I sold. They were such a A beautiful balance of monitor like
Frequency response, yet warm toned and completely disappeared.