  Coupled models of quintessence are usually introduced for avoiding or
mitigating the parameter fine-tuning problem. At the same time, the coupled
models should avoid the fine-tuning problem related to the initial conditions
as quintessence models do. One more attractive feature of coupled models might
be the explanation of the timescale at which the coincidence of DE and matter
energy densities occur and the understanding of reason why after this the DE
takes over. And finally, all these nice features should be unaffected by the
quantum corrections of the potential. Having in mind these remarks, we shall
focus our discussion on mass varying neutrino model of DE with inverse
power-law potential to see how naturally does it work.
