The enemy may be low on ammo. The easy way is always mined. Incoming fire has the right of way. Tracers work both ways. The only thing more accurate than incoming enemy fire is incoming friendly fire.
Professional soldiers are predictable, but the world is full of amateurs.
Murphy was a grunt. This is from the very first US Special Forces group. This advice is still useful today. Don't forget nothing. Have your musket clean as a whistle, hatchet scoured, sixty rounds powder and ball, and be ready to march at a minute's warning.