  We give a review of the theoretical status of the lifetime predictions in the
standard model. In case of $(\Delta \Gamma/ \Gamma)_{B_s}$ we are already in a
rather advanced stage. We obtain
$(\Delta\Gamma/\Gamma)_{B_s}=(9.3^{+3.4}_{-4.6})%$. It seems to be difficult to
improve these errors substantially. In addition now some experimental results
are available. For $\tau_{B^+}/\tau_{B_d}$ and $\tau_{\Lambda_b} / \tau_{B_d}$
the theoretical status is much less advanced and the discrepancy between
experiment and theory still remains. We conclude with a what-to-do-list for
theorists.
