The search for lepton creation and Majorana neutrinos with double-beta decays is about to enter
a new era. Several ton-scale experiments are in preparation to explore the full parameter space
allowed by theories predicting inverted-ordered neutrino masses. In this paper, we evaluate the
discovery probability of a combined analysis of such a multi-experiment endeavor assuming the
complementary scenario, in which neutrino masses are normally ordered. The discovery probability
strongly depends on the mass value of the lightest neutrino, ranging from 0 probability in case of
vanishing lightest neutrino masses, up to 87% for mass values just beyond the current constraints.
We study discovery probability for a selection of priors on the lightest neutrino mass, including ex-
citing possible future scenarios in which cosmological surveys measure the sum of neutrino masses.
Uncertainties of nuclear calculations which influence all experiments are also evaluated and found to
partially compensate each other when data from different isotopes are available. Although discovery
is far from being granted, the theoretical motivations for these searches and the presence of sce-
narios with high discovery probability strongly motivate the proposed international, multi-isotope