The status of heavy quark expansions for charm and beauty lifetime ratios isreviewed. Taking note of the surprising semiquantitative success of thisdescription for charm hadrons I interprete the new data on $\tau (D_s)$ andre-iterate the call for more precise measurements of $\tau (\Xi_c^{0,+})$ and$\tau (\Omega_c)$. A slightly larger $B^-$ than $B_d$ lifetime is starting toemerge as predicted; the largest lifetime difference in the beauty sector,namely in $\tau (B_c)$ vs. $\tau (B)$ has correctly been predicted; the problemposed by the short $\Lambda_b$ lifetime remains. The need for more accuratedata also on $\tau (B_s)$ and $\tau (\Xi_b^{-,0})$ is emphasized. I discussquark-hadron duality as the central theoretical issue at stake here.
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