I have accumulated lots of fat quarters that I am trying to use up (and not buying more) - Now I don't buy any fat quarters unless I have an immediate need/use.
Re the yardage type of stash - I had some that I have accumulated, and some that I was given. The stuff I was given isn't all to my taste and if I don't start to use it soon I'm going to give to the guild for charity quilts. The stuff I purchased I really like (still) and I am using it up as much as I can.
I also see it as a reserve fund for when I want to quilt but don't have money for new fabric or don't want to go out to shop.