What do you count as clutter? I am doing the 2013 in 2013 and don't want too cheat myself of the full count!
i think it's a rather efficient psychological trick .... now that i'm commited to counting, i focus on the counting .... and sometimes (not all the time, i still have plastic bags i've moved INSTEAD of sorthing through them) well, the focus is taken away from the pain i have at parting from stuff (anxiety about loss ? fear of failing to do "the right choice" ? etc ....)
and i'm even going on with my daily life and suddently think "when i'm coming back home, i could take this item from that place and put it in the trash/put it in the donation bag/ ...")
so, keeping a count of the stuff i part with has helped me start the process of "stopping to keep everything by inertia" ....
That would simply be impossible in our case. We recently finally sorted through legal documents from dh's old business, plus two law suits. This was tens of thousands of pieces of paper. But I want credit for that in my 2013-in-2013 effort, dammit! :D So I counted how many boxes of paper we took to be shredded. It still ended up being 11 boxes, a pretty good addition to my total.
Same with my kids' arts and crafts, when they were little. My kids are teens now. When I was sorting recently I kept a few of their pieces tucked away, I know I'll enjoy looking at them 10 years from now. But the rest of them had been piling up in under-bed-bins and I had no problem just tossing them all in the recycle bin. And I counted each kid's stack of art as one on in my 2013 count.
If you don't have that many, or you don't mind counting, go ahead and count them all.
Edited for clarity.