Static wick tech.
I read with interest the static wick article in the July 2016 issue of Aviation Consumer. If I recall correctly from a long time ago, static wicks can be tested for proper operation. I'm thinking it is a resistance test performed with a meter.
Assuming there actually is a way to determine the condition of the wick, it would have been helpful if you had included that information. If there isn't, that information would also be useful. As it stands, the article seems to fall short.
During our research, we asked static wick manufacturers about ICAW procedures (instructions for continued airworthiness) and all noted that aside from a preflight visual inspection, it's important to look for signs of corrosion where the wick attaches to the skin. Additionally, you'll want to inspect the tips. Testing rarely happens on the shop level.
TCO's Jon Snider told us the company measures the discharger with a megohm-meter during the production process, but noted that most shops don't have access to this type of meter. These things can wear out. Snider said TCO discharge wicks are worn out when the corona points (the conductive fibers at the end of the wick) are no longer visible. All manufacturers and shops we spoke with agreed that wicks break off the aircraft far more frequently than they wear out.