I turn off the bias when not listening. That’s what I’ve done with the A-1PX panels I’ve owned since January 2012 (8+ years) and I’ve experienced no breakdown issues. Prior to the A-1PXs, I owned two different versions of M-1s and M-3s (pre and post ~2006 insulation) which I left bias-on 24/7. Both eventually had breakdown issues. Perhaps my breakdown issues were simply bad luck and had nothing to do with 24/7 bias … but my luck has been better by turning off the bias when not in use.