I live in a one bedroom apartment with my husband and dog, so I have pretty tight constraints on how much I can stash (I have spinning, sewing, needlepoint and cross-stitch to contend with as well). The nice thing about this is that it forces me to mostly put things in bins:
-Two giant ones for fiber and yarn (in the living room which is not optimal).
-One biggish one for fabric (in our storage closet).
-Four small to medium ones for needlepoint and cross-stitch in our hall closet).
The issue I struggle with is the proliferation of UFOs and just-bought yarn in project bags which are in a huge and uninspiring pile next to my crafting chair. I haven't made any meaningful effort to organize them for easy access. Full disclosure, my therapist thinks I should as regular crafting helps me stay centered.
I do a few different things to keep the yarn/knitting at status quo:
-I frog things ASAP after realizing that they no longer interest me. I wash and either repurpose the yarn or donate. I use my project page on Ravelry to asses candidates for frogging whenever I feel like I have too much on the needles.
-I "air the stash" at least once a year and donate yarn that no longer speaks to my heart. Some of it is value/workhorse yarns and some of it is fancy/expensive and some of it are oddballs. I have no rules about it other than it no longer speaking to me.
-I have two scrappy afghans, one in progress and one planned, one for my worsted leftovers and one for my fingering weight leftovers.
-It's not frugal, but I rigorously discard scraps that cannot be used for anything. If it is smaller than can be used for mitered squares (i.e., "my scrapghans;" each square uses only two colors which is a decent amount of yarn) or repairs of FOs, it goes.
I haven't figured out any strategies yet for my other crafts, but they seem contained enough that I am not too worried about it. Helps that my tastes in needlepoint and cross-stitch run to the, ahem, very expensive so I buy very little.