How long are the smallest red dwarfs predicted to burn on the main sequence?

Answer

Trillions of years

Because they consume nearly all their hydrogen fuel due to full convection, the smallest red dwarfs are predicted to have lifespans extending for trillions of years, far exceeding the current age of the universe.

How long are the smallest red dwarfs predicted to burn on the main sequence?
astronomytemperaturestarmain-sequence