I wonder the same thing. I have a friend that converted her doubloe car garage into her sewing room. She has all her fabric in closed containers marked. Christmas, Easter, ST Patrics, pinks, greens, and the list goes on.
It is amazing the yardage and scraps she has.
I guess it depends upon how many years a person has been quilting. Some of us don't have the will power not to buy.
Good luck building your stach.