A strap you haven't tested is a strap you're wearing for comfort.
What the tester measures
A wrist strap tester checks the complete loop: band, cord, contact and the wearer's skin, verifying total resistance sits within the specified range. Too high means a broken path; too low can mean a shorted cord, which is also unsafe.
The daily ritual matters because cords fail internally with no visible sign.
Handling marginal results
Failures usually trace to contact: dry skin, loose band, dirty electrode. Adjust and retest before swapping parts.
Persistent marginal readings point to skin condition or cord wear — replace the cord first, it is the cheaper and more frequent culprit.
FAQ
How often should wrist straps be tested?
Commonly at the start of each shift when the strap is used daily; logs make the habit auditable.
Can two people share a tester?
Yes, that is normal; the log should still attribute each test to a wearer.
Do wireless (cordless) straps replace testing?
Cordless straps are controversial because the discharge path is hard to verify; most ESD programs rely on corded straps with daily testing.
All figures above refer to standard product data sheets; final confirmation is subject to written quotation.