  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.
