Did your friend ever try the freezer trick? Mine had the same cracking issue and it turned out the mylar was fine, but her garage was too cold so the crimp never set right. She started warming the dies on a heating pad before runs and the cracks stopped almost overnight.

Only needed two cord swaps" is the most beautiful sentence I've read all week. My fancy cordless one dies mid fade and I'm standing there like an idiot holding a dead brick, so yeah the old plug in stays in the drawer.

That heat shrink trick is the same thing as putting tape over your phone flashlight when you lose something in the car, the bright light is actually the problem, not the fix. Half the wins in this life come from dumb little changes like that, the kind nobody teaches because they seem too small to matter. The old guys on the ramp know them all and they just hand em out like candy if you stand there long enough.