Hi Guys

According to the late-time evolution modelling by Adams, Bodenheimer and Laughlin M-stars will last for trillions of years. A minimum mass star, 0.08 m(sol), will hydrogen burn for 11 trillion years, a 0.1 m(sol) star 6 trillion, and at least a trillion even up to 0.25 m(sol). So M stars are stable for immense periods. They evolve very, very slowly.

Part of the longevity is due to their deep convection which means most of their mass goes through the core - unlike the Sun which segregates the core from the rest. Only about 10%of the Sun will go through the core's fusion processes before the Red Giant stage.

Adam