I buy yardage but mostly jelly rolls, a few layer cakes and charm packs.
I like pre-cuts simply because I don't have easy access to fabric stores and
they are already matched for me. :) I buy my fabric online mostly. When
buying pre-cuts I find it more useful to choose the pattern first otherwise
you could get stuck with the wrong cut or not enough. For example, there
are patterns for jelly rolls that are not really suited for layer cakes...like
sewing long strips. You could use layer cakes and cut strips but you could
end up buying twice as much fabric and a lot of waste. Hope this helps.