I have posted about this before but basically I go through my photos that haven't been scrapped and kits that haven't been used and pair them together. If I can't find a kit for some photos or some photos for a kit, they go in separate folders in addition to the chronological folders I have for all my photos and the kits I have (sorted by designer) for all my stash.
I delete a kit after using it once about 75% of the time so my stash is not nearly as large as it could be (I've been digitally scrapping for 17 years now). I also don't usually keep kits or elements for more than 3 years or so with exceptions for templates and a handful of neutral alphas. My entire photo collection, layouts from 2003 until now, and my stash only take up 463 GB on my EHD so I'm pretty ruthless about culling what I won't use or is outdated.
