Several weeks ago, I noticed something odd about a phone I had been using for a while: tiny bits of dust and pocket lint were stuck in a gap between its metal frame and glass back plate. I tried to push the particles out of the crevice and – to my surprise – a gap opened between the glass and the frame it was supposed to be glued to. The adhesive in that particular area had become loose, apparently.

This wasn't a good thing. Although the phone still looked fine to the naked eye, it had most likely lost its water-resistant properties. Its out-of-the-box IP68 rating couldn't be trusted anymore. ...