Most fly rods break as a result of human stupidity. Of course, many rods carry a no-fault warranty (meaning we’re already paying, in advance, for the replacement or repair of broken rods), which is probably why we’re careless and slam rods in screen doors and tailgates, walk them into trees, step on them, and so forth.
Sure, there are lemon rods that will break when fish pull on them. But operator error–whether that’s casting a heavy fly into your own rod tip, or allowing a fish to run under the boat–is usually what causes breakage.
The number one human cause of broken rods is a simple move many of us instinctively make, and most of us don’t realize we’re doing it, or that it’s a problem.
When you’re fighting the fish, you want to get more leverage, so you instinctively grab up on the rod. Problem is, the rod was designed to flex in that area above the handle, and when you make that an anchor point, you shift the pressure there, to a smaller-diameter and more vulnerable part of the rod. The rod is far more likely to break when you reach up and grab above the handle than it is if you keep your hands on the cork where they belong. I’ve seen many rods intentionally broken for testing purposes, and this move is the surest way to make them shatter.
So keep that in mind, and tell your fishing buddy who grabs the rod to let go. You’ll save him/her the headache of a broken rod, and the rest of us the built-in expense of paying for it.