Ever regret not buying something?
I've bought waaaay too much stuff over the years as it is. I regret buying quite a few things. I can't think of anything I regret NOT buying.
Yes, many years ago had a Cary CAD 300 SEI in my house, and could have bought it very cheap. I just didn't have a suitable speaker for this SET, so passed on the purchase. Now even earlier models, like the one had, sell for much more than I would have paid.
As far as tuners, I did buy a HH Scott 4310 many years ago for $500, and now they sell in that Marantz 10b price range, and sometimes higher.