We review current status of theoretical predictions of lifetimes of heavy
hadrons in heavy-quark expansion. We present a calculation of subleading 1/m_b
corrections to spectator effects in the ratios of beauty hadron lifetimes. We
find that these effects are sizable and should be taken into account in
systematic analyses of heavy hadron lifetimes. In particular, the inclusion of
1/m_b corrections brings into agreement the theoretical predictions and
experimental observations of the ratio of lifetimes of Lambda_b-baryon and B_d
meson. We obtain \tau(B_u)/\tau(B_d) = 1.09 \pm 0.03, \tau(B_s)/\tau(B_d)= 1.00
\pm 0.01, \tau(\Lambda_b)/\tau(B_d)= 0.87 \pm 0.05.Comment: 10 pages, 4 figures. Invited talk at the workshop `Continuous
Advances in QCD 2004', Minneapolis, Minnesota, May 13-16 200