Fusible link question

[Chrispbrown36]

I spent 4 hours in the Tractor Supply parking lot replacing the ignition switch and trying to find a short in my ignition wiring and finally having it towed home. First thing I did was hop on here and everything pointed to the fusible link on the fire wall. I strapped on the headlamp and headed out there. Sure enough the fusible link was melted in half. So my question is....do they just fail from age or should I be looking for some other problem down the line that made the link melt? The truck is an 87 V10. The link appears to be original.