One person's trash, is always another persons treasure.
The one machine that I have sold, through the years, that I have truly regretted, was a Performax 16/32. What a pain in the behind machine it was.You couldn't keep the depth consistent on that machine to save your life, and I did a lot of big work with it. But I went through a period of veneering, after I sold it, where it would have been perfect. Set it and forget it, lock it in place by any means, and go.
I've bought more than a few things on Craigslist, that would have been a pass for a lot of folks, but I've saved some significant $$$$ I have two Ponsness Warren shotgun shell reloaders that are close to 50 years old, that I bought for peanuts;. A weekend of work, $20.00 investment in an end mill and a ball mill, and they now work as new.
Bottom line: You just never know.
"The first thing you need to know, will likely be the last thing you learn." (Unknown)