I realized that I have this problem. You see, it's very easy to buy cars. It's also extremely easy to buy parts for cars. And, if you have the money, I suppose you could buy someone's time to put those parts you bought on those cars you bought.
Unfortunately, while I (and, I feel, most of us here) have both car money and parts money, very few people have "pay someone to put those parts on" money. That, and we probably actually enjoy that part of the process. Unfortunately, there's only so much TIME...
When we moved recently, I sold off half of the project cars that I own. This amounted to somewhere in the neighborhood of 15 or 16 cars. In the process of doing that, I noted that not only was this about 10,000 dollars worth of cars, but for each of these projects I had also bought parts. The stock of fenders, gasket kits, weatherstripping, emblems, engines, transmissions, electrical parts, windshield wipers...etc was probably another $5000 in parts.
And truthfully, I don't miss any of those cars that I sold. In fact, I'd have sold more if I could have found homes for them. I won't crush something unless it's absolutely hopeless (wrecked or rusted out).
It's called Automotive ADD (AADD for short) and I'm slowly trying to cure myself. And like a smoker, occassionally I lapse. I made a set of rules for myself for new car purchases. All new car purchases much meet the following criteria:
1) Must have a title, or be a parts car for a vehicle I already own
2) May be any Volvo Amazon or 1800 under $500
3) May be any car bought for under scrap value, including my time/gas to go pick it up
And I recently found myself dragging home a rusted-out 1952 Nash, because it has a title and was cheap. My wife shakes her head.