  A phenomenological model with itinerant bands and local states trapped by the
lattice on the Cu-sites, is discussed to describe global features of cuprates.
Relative energy positions of localized and itinerant states being tuned
(thermodynamically or by doping), the system must undergo 1st order Mott
metal-insulator transition. Decreasing the local level (from the metallic end
of a stoichiometric compound), charge separation instability occurs first
before the Mott transition. Crossing and hybridization between local (flat) and
itinerant bands introduce a structure in density of states which may account
for ``pseudogap'' features in cuprates. Model results in polaronic lattice
effects and is rich enough to serve as a phenomenology of cuprates.
