Theoretical status of the lifetime predictions: $(\mathrm{\Delta }\mathrm{\Gamma }\mathrm{/}\mathrm{\Gamma }{)}_{B_s},{\tau }_{B^{+}}\mathrm{/}{\tau }_{B_d}$ and ${\tau }_{{\mathrm{\Lambda }}_b}\mathrm{/}{\tau }_{B_d}$

We give a review of the theoretical status of the lifetime predictions in the standard model. In case of $(\mathrm{\Delta }\mathrm{\Gamma }\mathrm{/}\mathrm{\Gamma }{)}_{B_s}$ we are already in a rather advanced stage. We obtain $(\mathrm{\Delta }\mathrm{\Gamma }\mathrm{/}\mathrm{\Gamma }{)}_{B_s}=(9.3_{-4.6}^{+3.4})$. It seems to be difficult to improve these errors substantially. In addition now some experimental results are available. For ${\tau }_{B^{+}}\mathrm{/}{\tau }_{B_d}$ and ${\tau }_{{\mathrm{\Lambda }}_b}\mathrm{/}{\tau }_{B_d}$ 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.