Theoretical status of the lifetime predictions: (ΔΓ/Γ)B_s, τ_B+/τ_Bd and τ_Λb/τ_Bd

We give a review of the theoretical status of the lifetime predictions in the standard model. In case of (ΔΓ/Γ)_Bs we are already in a rather advanced stage. We obtain . It seems to be difficult to improve these errors substantially. In addition now some experimental results are available. For τ_B+/τ_Bd and τ_Λb/τ_Bd 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.