Ok, so here's my stance. I, at one time, had a collection of about 150 models. I had just gotten married, had bills, not enough time, yada yada. I put the collection on ebay and sold everything, and I mean everything (except for the few finished cars and the one half-started car I had) for pennies on the dollar. You don't even want to know!
Then, fast forward a couple of years. I decide to finish the one "in-progress" car I had. That of course sparks the fire again. This time I played it smart. Here's what I did:
I made a list. I listed the kits that I built as a kid that I would like to try as an adult. I listed the kits that I remembered being so cool and influential. I listed the "gotta-haves". So now, I have roughly 85 un-started kits on shelves in my closet, along with about a dozen or so misc cars, whether they are built-ups needing restoration I've picked up from ebay, or resin kits, or parts cars I haven't given up on yet. So other than some of the releases or re-releases that come out that I just gotta have, for the most part, I'm done (except for the 9 or so that are still on the list) .
As far as my finished builds as an adult, I've got 9. The first of those was completed 10 years ago last month. So in doing the math that you all do, I end up completing just less than 1 a year. So I'm 34 now, if I continue on this same path I will finish my last one when I'm approximately 134 years old. So, this "list" I figure, is a good way to go. I have no business buying any new kits not on the list!