I've recently learned that old air compressor tanks can catastrophically fail. I can't find anything about the average service life of a tank, but it appears the ones that do explode are typically fairly old (they appear to be around 40 years old).
What is the simplest way to test an air compressor tank? How frequently should this test be performed?
From what I understand, the only option is to hydrostatic test the tank to about double the working pressure. The options are to use a pressure washer (with water), a grease gun (which may be difficult to use water), or a hydraulic pump modified to use water, each of which require about $100 of equipment.