If I understand correctly, red dwarfs consume all of their hydrogen and will eventually shrink into helium white dwarfs, whereas the higher mass stars will consume a fair amount of their hydrogen fuel, not necessarily all of it. Correct me if I'm wrong.
Stars less than about 0.3 solar masses are fully convective, so hydrogen throughout the entire star can be transported to the core and consumed. At higher masses, the core is radiative, so only hydrogen that starts in the core is consumed.
$\begingroup$ The core of stars more massive than about 1.3 times the Sun are convective. $\endgroup$– ProfRobDec 9, 2017 at 20:19
$\begingroup$ True, but the convection doesn't extend to the envelope, so no new hydrogen is added. $\endgroup$ Dec 9, 2017 at 22:58
$\begingroup$ Do massive stars consume hydrogen in the shell during the red supergiant phase? $\endgroup$ Dec 20, 2017 at 12:51
$\begingroup$ Yes, although the shell is not replenished with hydrogen from the envelope. $\endgroup$ Dec 20, 2017 at 21:51