I've usually bitten when I see a good deal. My problem is some of the ones I have sold never thinking about what they might do in the future.
I had an almost perfect TZ I sold for $2900. I never thought ANYONE would pay more than that for a TZ. When I paid $2300 for it, people thought I was crazy.
I also sold a Fathom for around 2k which was beautiful. Again, nobody was ever going to convince me that a Bally SS game would ever go for more.