  Accurate mass-loss rates are essential for meaningful stellar evolutionary
models. For massive single stars with initial masses between 8 - 30\msun the
implementation of cool supergiant mass loss in stellar models strongly affects
the resulting evolution, and the most commonly used prescription for these
cool-star phases is that of de Jager. Recently, we published a new \mdot\
prescription calibrated to RSGs with initial masses between 10 - 25\msun, which
unlike previous prescriptions does not over estimate \mdot\ for the most
massive stars. Here, we carry out a comparative study to the MESA-MIST models,
in which we test the effect of altering mass-loss by recomputing the evolution
of stars with masses 12-27\msun\ with the new \mdot-prescription implemented.
We show that while the evolutionary tracks in the HR diagram of the stars do
not change appreciably, the mass of the H-rich envelope at core-collapse is
drastically increased compared to models using the de Jager prescription. This
increased envelope mass would have a strong impact on the Type II-P SN
lightcurve, and would not allow stars under 30\msun\ to evolve back to the blue
and explode as H-poor SN. We also predict that the amount of H-envelope around
single stars at explosion should be correlated with initial mass, and we
discuss the prospects of using this as a method of determining progenitor
masses from supernova light curves.
