It totally depends on whether or not I like the line. If I like something else in the same line, I'd use it. If not, I'd seek other coordinating fabrics. I rarely want to use all the fabrics in a line.
I totally agree. Whenever I buy charm packs or even look at them online, I generally find I only like about a quarter of the fabrics. I can't imagine forcing myself to use only fabrics from one line, unless I happened to like all of those fabrics.