Once hairs sprout from your scalp, it's no longer growing -- they're just growing older. Hair on the end of a strand, or shaft, can be up to six years old. It's seen a lot of wear and tear. Also, hair naturally loses moisture with age. The protective outer covering (the cuticle) can split at the ends, which can move farther up the shaft and lead to further weakness, dryness and damage.
A regular trim helps nip the problem in the bud. Hair strength varies with genes, washing routine and other treatments, and exposure to sun and heat, so some guys can go longer between cuts than others. Because the cuticle reflects light, dull hair is a sign that the cuticle is cracking up. Act soon to avoid a head full of frizzies.
Our last piece of advice is something most people agree on.