The more time you spend on trail the more you can benefit from a bit of thought about your own personal mechanics. In one last spring training video before my backpacking season kicks into high gear I spend a few minutes focusing on form and how our function on trail is directly related to how we use our bodies. See if taking a little time to think about how you hike can bring you a bit more happiness out there!
Less traveled by 
Hard for me to consider form when I’m exhausted.
That is exactly the point Richard! The idea is to practice good form always so that you stay in that form even though you are exhausted. It is like practicing for a sport so you have muscle memory when playing at game speed. Even when you get too tired to feel your legs they still know what to do 🙂