I've run the whole spectrum.
Age, weight and fitness play a role.
Me 57 and now carry 20 lbs more than I should = I need more boot.
Last year did a 3 day backpack with a light, low-cut trail runner (Sportiva Wildcats.. love 'em). Descending I'd get bad ankle roll. Had to tape ankles.
This year I am finding my ankle rolling is a concern, but extra weight makes it hard on feet. I've been using heavy Asolo boots and they make me slower, but add comfort and safety. YMMV.
