Pick a trail shoe by terrain first. Soft, muddy ground needs 5 mm lugs and a snug heel; hard-packed fire roads need less grip and more cushion. A rock plate helps on sharp scree. Wide feet: look for a roomy toe box (Altra, Topo) rather than sizing up.
Drop matters less than fit. If you're coming from road shoes with a 10 mm drop, move down gradually.
