When I first started seeing leds I thought they were going to last forever ... and I don't recall changing any in the first 20 years or more ... but now I see them crook quite regularly.
One thing that surprised me is that they don't like direct sunlight. Eg. In a rotary dairy where the platform stops for several hours in one spot ... those exposed to sunlight get horribly faded ... but other's that don't get much sun ... still look really good.
I'd also suggest that sunlight bothers them more if they are illuminated ... more so than if they are not. That comes from recent experience with a roadside led sign.