Degradation studies with over 235 000 device hours have been performed on single‐quantum‐well AlGaAs lasers with uncoated and half‐wavelength Al2O3‐coated facets at stress levels ranging from below threshold up to optical power densities of 23 mW per &mgr;m facet width. The effectiveness of facet protection has been investigated with respect to gradual degradation and catastrophic failures. Facet protection is very important for obtaining long lifetimes and improved immunity to sudden catastrophic failures. With facet coatings, degradation rates as low as 0.18%/kh have been measured at 30 mW in single‐lateral‐mode operation and at 50 °C.