Here's the formula for how many NIB or otherwise unbuilt (or rebuildable) kits one needs...N + 1 = Y,with "N" being the current number of kits presently in your stash already,and "Y" being the number of kits your stash needs to be complete. I short,regardless of how many kits you have,you always need one more. You can tell your wife that Olkoolrodder said so,and it's ok,he's a professional (notice I didn't say professional "what" ),and after she stops yelling or laughing (depending on her disposition),don't feel too badly,it didn't work on my wife neither
Seriously,though... had a several hundred kit stash before we had a house fire last year-while that was probably (most assuredly,actually) more kits than I'd ever build,it's hard to not buy something when you see it,knowing you'd enjoy building it because if you don't get it,sooner or later (assuming you still want it) you'll end up having issue finding a copy,and then pay too much for it on eBay or similiar. Also,I like to have a few extra kits laying around because one never knows when brother-in-plastic will have life jump up and bite em hard (like our fire last year),and I like to be able to help out (I can say with much admiration and appreciation that model building internet friends went way above friendship when we lost everything,sending anything frm money to help cover motel expenses,to clothing for us and the kids,and once settled later,lots of kits and supplies to build them with),besides that there's always more tha one way to build any given kit,and parts in every new kit box that would be just perfect for that other project.....
There has to be a fine line somewhere though,or oe could wind up overflowing their space to store,or even become obssessive with "the hunt" for the next kit buy I can't say what that line would be for ANYone (even myself,it seems ). Some people are perfectly happy owning one or two,including current WIP's,some people get their joy looking at a vast collection just waiting to be built,it's really a personal call. Does one HAVE TO HAVE the latest kits coming out (or that elusive hard to find NIB classic) sitting in their stash to be happy or a part of the community? No,but it can be fun to do so and there's nothing wrong with that either,IMHO.