If a fixture is rated for 100,000 hours how long will it last?

The length of time a fixture can last is based on how long a fixture is illuminated per day.

Based on hours of operation, 100,000 hours is:

24 hours per day  = 11.4 years
18 hours per day  = 14.8 years
12 hours per day  = 22.8 years
8 hours per day  = 34.2 years