A number of people have said it here or there, but for me it has been a case of as I evolve as a rider/enthusiast/whatever, coupled with expanding knowledge and interest, plus not being 5 or 10 years (or name your time frame) younger and thus not wanting to put up with certain things, that Grail changes (and thus it never ends). I know my riding style better, I know my fitment better, I know I don't want to get jackhammered on city streets, etc. I love a lot of vintage frames/bikes, namely early full Reynolds 531 Treks in their tallest size (as it fits me), but modern frames will surprise me in that it's not--as a road/race frame-preferring guy--the tip of the spear race bikes and exotically-constructed frames that I end up liking. This is me with my Trek 1.5 and FX 7.3. The FX also has gorgeous paint, and outright beauty/not having to repaint/re-coat a bike plays into the "logic" for keeping or selling or hunting.

I do find myself thinking about old frames/bikes I've had that I now would like back as my preferences have changed and knowledge increased. A bit of this is driven by wanting a little more tire clearance on a race bike frame. Thankfully, and ultimately, I don't need to worry about that as I have a touring bike (a touring bike!) that does all of the fast bike things just a hair less fast but a lot more comfortably. And yes it's a 531 Trek. Sometimes we just want things, or we are simply curious about them for any number of reasons. Accidental Grail can be the best kind of Grail.