  Even if new data indicate that direct CP violation in D-meson decays is
compatible with the standard model expectation, it has triggered a lot of
interest, and charm phenomenology will remain an essential part of new physics
searches due to its unique role as a probe for flavor-changing neutral currents
among up-type quarks. Charm physics poses considerable theoretical challenges,
because the charm mass is neither light nor truly heavy. The heavy quark
expansion (HQE) provides a perturbative expansion in the inverse heavy quark
mass for inclusive rates. It has proved to be very successful in the B sector,
yet its validity for charm decays has often been questioned. We present results
of a HQE study of D-meson lifetimes including NLO QCD and subleading 1/m_c
corrections. We find good agreement with experimental data, but with huge
hadronic uncertainties due to missing lattice input for hadronic matrix
elements.
