LED's (the diodes themselves) when properly controlled electrically will operate for up to 100 years with virtually no decrease in light output. The problem is the controllers used. Most are made in China and the quality is all over the world. Poor quality controllers will give poor performing and lasting LED's. Stick with major manufacturers and avoid "the cheapest you can find on e-bay". No one is making a perfect controller so the 100 years will never be attained, but a good LED system should perform well for many years, but you get what you pay for.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof