I rarely use more than 1/2 yard of any certain fabric in a quilt. So, no, I have no idea what fabrics are in my stash.
However, they are organized so that if I want a red, civil war reproduction print I can put my fingers on where it would be if I have it. If I don't have it - oh well - pick out something else. Same thing with all of the fabric types (flannels, blue blenders, neutrals, large multi-colored florals, holiday, denim, yellow check, black & white, white & black, solid green, etc..)
When I see a fabric in a store that I like I just pick up a yard or two and add it to my stash. That way, I always have fabric that I like on hand.
I can tell by the thickness of the fabric wad in my stash if it will be big enough for borders. I also piece the backs of large quilts so I don't need large yardage for that either.
As many have said, trying to keep inventory seems very time consuming for the number of fabrics I have.