For me its about the realisation that I'm not actually playing with or using the kit I have. I used to buy stuff because I had a interest in using it and although I am primarily a (retro) apple fan I did collect (in the sense that I purchased for the purpose of using) other brands of equipment. Over the years I would have a periodic clean out as I realised stuff had just sat in storage and not been used. First it was the non-apple stuff, then apple stuff that I didn't have a real connection with (i.e. equipment that I would have liked to have owned in the hay-day but didn't) until finally I'm left with really just the core stuff that got me interested in this whole computing thing in the first place - even that I don't really use however and so I occasionally (when I open my cupboard) think about getting rid of even that stuff.
I guess looking at the stuff and realising its just been sitting idle for the last 5 years makes me sad (does that sound stupid?), therefore, if I get rid of it I don't have to feel so bad about not getting around to doing anything with it.
Interestingly, although I love the original hardware, the last couple of times I have gone to use any kit, its involved a repair job or two first - so I have started to appreciate emulators more
So short answer? Time to actually do anything with it and the fear of becoming a hoarder