A number of recent observations promise to have a significant impact on semiconductor laser reliability. Device life has been seen to depend on device architecture and processing, epitaxial structure and growth parameters, and alloy chemistry. Comparative studies have shown that dry-etched devices are at least as reliable as oxide-defined lasers, and that median life is a function of the quantum well count in the structure. Improved reliability has also been obtained by using longer cavity devices to improve thermal performance at the lasing junction. Elimination or reduction in the occurrence of sudden or freak failures which limit median life of diodes has been achieved by studying the factors influencing the growth and propagation of dark line defects (DLDs). Operating temperature, chip geometry, alloy effects, and epitaxial growth parameters have all been shown to affect device reliability.