  Assuming Majorana neutrinos, we infer from oscillation data the expected
values of the parameters m_{nu_e} and m_{ee} probed by beta and 0nu2beta-decay
experiments. If neutrinos have a `normal hierarchy' we get the 90% CL ranges
|m_{ee}| = (0.7 - 4.6) meV, and discuss in which cases future experiments can
test this possibility. For `inverse hierarchy', we get |m_{ee}| = (12 - 57) meV
and m_{\nu_e} = (40 - 57) meV. The 0nu2beta data imply that almost degenerate
neutrinos are lighter than 1.05 h eV at 90% CL, competitive with the beta-decay
bound. We critically reanalyse the data that were recently used to claim an
evidence for 0nu2beta, and discuss their implications. Finally, we review the
predictions of flavour models for m_{ee} and theta_{13}.
