Well, when I bought each of the kits in my stash, I intended to build it - I even had an idea in mind at the time of exactly how I wanted to build it.
I also build other subjects - aircraft, real space and even have a couple of sci-fi kits.
My problem is my enthusiasm for each tends to vary a lot - and the pile of 'things I will build' tends to vary too. I also have a pile of 'why the hell did I buy that' which also has kits that come and go - all depends on the mood of the day!
Its still fun after all these years - and that is the most important factor.