This is standard now. My REC Alpha Pure Black 400 panels are warrantied for 92% at 25 years. The degradation is about 0.25%/yr. Assuming no exponential drop-of

This is standard now. My REC Alpha Pure Black 400 panels are warrantied for 92% at 25 years. The degradation is about 0.25%/yr. Assuming no exponential drop-off it would take >50 years to hit 80%. Essentially no one has had to replace their panels due to degradation losses as of yet (since the vast majority of panels have been installed in the past ~30 years).