The 70 °C dry nitrogen ambient, continuously operating, lasing lifetimes of 8‐ and 12‐&mgr;m stripe width proton‐bombardment‐delineated double heterostructure (Al,Ga)As lasers are compared. The different stripe‐width lasers are found not to exhibit significant lifetime differences for (slice dependent) median lifetimes less than about 1000 h at 70 °C. However, for median lifetimes greater than this the wider stripe lasers are statistically longer lived. In companion experiments the lasing lifetimes of devices with deep and shallow proton bombardment (protons penetrating, and not penetrating the active volume) have been found to be similar, with the possible exception of very long‐lived devices. In the latter case shallow bombarded devices may be superior. More experiments will be required to establish a causal relationship, if it exists, between proton damage in or near the active volume and laser lifetime.