If it is a fabric line, I usually buy 1 to 1 1/2 yards of my favorites (no more than 2 favorites), and 1/2 yard of the rest.
Lately, I have bought precuts (layer cakes, charm packs, jelly rolls) and a yard or so of 1 or 2 of my favorites, I find that most quilts do not call for 3 yards of one fabric and it also means I can buy more different fabric.
I think the ones buying the 3 yds or more will make a lot more quilts than I do. One are two of the same fabric is my limit and I am trying not to add to my stash.
So I guess it depends on how you quilt.