Any Keurig Owners Out There?

So I just got a shiny new Keurig coffee brewer as a gift, and I have a quick question that I can't seem to find the answer to. The maker came with a few sample flavors of coffee and tea. Am I supposed to rinse out the maker in between different flavors? Or does the machine do a good job of preventing the last flavor from bleeding in with the new one? Since I don't have too many K-cups right now, I'd rather not learn the hard way. Thanks!