If you're the type of rider that likes to ride downhill more than uphill, arm pump (forearm muscle swelling and soreness that can affect bike handling and braking) can be a frustrating problem. A quick tweak to your brakes and you could reduce arm pump and enjoy longer descents without the fatigue.
Adjust the brake part of the lever so it is very close to the grips. This keeps all your fingers close together. Some brakes have external adjusters and some have small internal adjusters. Use an allen key to make the adjustment. Only a few turns should do.