Because my long backpacking trips that I yearn to do are not exactly imminent (it's the dead of winter, for once thing, and the majority of my vacation time for 2014 is already "spoken for" on a number of trips--which will include some nice dayhiking with the family on a lengthy trip, but no several nights in the backcountry backpacking trips, sadly.) At the soonest, I'm looking at late winter 2015 for a Big Bend or Guadalupe Mountains trip, or spring 2015 Grand Canyon or southern Utah trip, or late summer 2015 anywhere in the classic mountains. This means that I'm not exactly running out to finish off my shopping list of backpacking gear, and picking up all of the things that I still need.
This doesn't mean that I'm not making an inventory and "wish list" of specific items I want to get and have ready for when that time comes, though.
However, I'm finding that making a list that will last long enough for me to actually buy the gear is more difficult than I thought. I've had to change the backpack on my list several times--sometimes because as I've done more research, I've found other models that I want, but surprisingly because one of my perenniel top contenders seems to have removed itself from common availability. I can still get it if I really want it, but only from one of three outlets, where it used to be readily available everywhere.
I later picked up a new favorite, after it got a really high recommendation from Backpacker Magazine, and it promptly became unavailble other than through special order. Did demand exceed supply? Dunno.
I suppose it's not a big deal, until I'm ready to actually go pick up my backpack, but it's a little frustrating that I can't plan what backpack that will be unless I just go buy it now.