In the guitar world, this is a failure of laminated composite materials. When stressed by excessive moisture or dryness, along with the kind of punishment any guitar gets when played hard, layers begin to separate, forming a mica-like structure of separate layers with significant loss of structural integrity. Delamination is insidious, as it develops inside of materials, without being obvious on the surface. Thus structural failure appears to be sudden. Many of the guitars built in the 1950s through the 1960s were prone to delamination because the instruments weren’t always built under optimal conditions. Most factories didn’t have air conditioning, so a guitar made on a hot, humid day in August or in the middle of winter with heaters constantly drying the air would certainly be at risk. Today, temperature and humidity are constantly being monitored year round to assure that each instrument is built under ideal conditions.