  We study with ARPES the renormalization and quasiparticle lifetimes of the
$d_{xy}$ and $d_{xz}$/$d_{yz}$ orbitals in two iron pnictides, LiFeAs and
Ba(Fe$_{0.92}$Co$_{0.08}$)$_2$As$_2$ (Co8). We find that both quantities depend
on orbital character rather than on the position on the Fermi Surface (for
example hole or electron pocket). In LiFeAs, the renormalizations are larger
for $d_{xy}$, while they are similar on both types of orbitals in Co8. The most
salient feature, which proved robust against all the ARPES caveats we could
think of, is that the lifetimes for $d_{xy}$ exhibit a markedly different
behavior than those for $d_{xz}$/$d_{yz}$. They have smaller values near $E_F$
and exhibit larger $\omega$ and temperature dependences. While the behavior of
$d_{xy}$ is compatible with a Fermi liquid description, it is not the case for
$d_{xz}$/$d_{yz}$. This situation should have important consequences for the
physics of iron pnictides, which have not been considered up to now. More
generally, it raises interesting questions on how a Fermi liquid regime can be
established in a multiband system with small effective bandwidths.
