The assumption is that a traditional incandescent or halogen bulb has a useful life of 1000 hours, this is the normal annual use. The compact fluorescent life span is 10,000 hours, while LED bulbs have a useful life of 25,000 hoursThese are all based on an average operating time of eight hours per day.
Although, initially, incandescent bulbs seem the better option because they're inexpensive, our calculator proves that over time they work out seriously expensive. In a lot of cases fluorescent bulbs don't represent a huge saving to LED.