Wrote off chain checkers for 8 years, then a $12 one caught a stretched chain I missed by feel
Last Tuesday a customer's rear derailleur was ghost shifting and I swore the cassette and hanger were fine, but my new $12 chain checker read 0.75 on a chain I'd called good by hand. Now I'm second guessing every chain I've eyeballed, so what's your cutoff for actually trusting the tool over your hands?