Planet June's Shrink Plastic Ring Tutorial

I've dabbled in making shrink plastic rings before, but never had any come out to my satisfaction. If I try it again, I'll definitely be using the instructions here courtesy of craft blogger Planet June.

While we're on the subject: anyone out there with experience wearing shrink plastic rings? I'm wondering if the slight expansion/contraction of taking a ring on and off your finger might be enough to cause small fractures in the plastic that would cause it to weaken and crack over time...