All lamps are equipped with high-quality LED light sources. The expected burn time differ to some extent, but you can expect 15.000-35.000 hours. If the light source is only on when it is dark outside it can last more than 10 years.

It's worth noting something called T70. This is a standard for how life expectancy is measured in (LED) light sources. The light source is considered "dead" when only 70% of the original light emitted is left. 

In other words, your lights will most likely function long atfer these 15.000 - 35.000 hours. Just giving a bit less light than they did at first.