This is an aspect of the hobby thats very difficult to avoid ,my own small stash of about10 kits is slowly growing even though I consciously try not to ,the reason why I think is easy,when we were kids we either had to use our limited pocket money (if you got any) or had to plead with parents,now as adults with our own income there is much less restraint and so we buy what we want.
I went to a large club day in the U.K. last weekend (Cosford) and saw one of our club members spend about £400 on kits which will probably never get built, another club member who is about 40 years old, and who's work regularly wins first prizes at national level comps, has worked out that that if he builds a kit every two months steadily for the rest of his life,asuming he has a normal lifespan, he will not complete all the kits in his stash and he's still buying more,he can laugh as he says it though.I know one guy who's been into the hobby all his life,in his 50's now who's stash is in thousands -literaly!.
Of course the next problem is what to do with them once built, I keep em for a while and then stick em on Ebay unless they go into the catorgary of "favourites".
N.