Quo Vadis, Fascinum?

The recent progress in our understanding of heavy-flavour decays allows us to define more reliably which future measurements on charm decays are needed to further advance our understanding of QCD and to get our theoretical tools ready for treating beauty decays. After sketching the theoretical landscape I list those required measurements. I argue that some -- in particular those concerning inclusive semileptonic charm decays and their lepton spectra -- can presumably be performed only at a tau-charm factory.