When I joined this site back in 2007, I had no concept of what a 'shelfer' was. Why have a model that can move under its own power if it never does?
Times have changed, and now more than half of my models (roughly 30 these days) never turn a wheel. It's enough to pick them up off the shelf and spin a wheel now and then, squish the suspension down a couple of times, dust them off, and put them back. I have my runners, as well, but for most of the 'special' ones, just having them is enough.
I still have yet to keep any kit NIB for more than a few months, however...