You Rarely Get the Rated Life of a CFL
Get used to frequent recycling. One of the biggest myths in all the CFL hype is the rated life of the bulb. You'll see blog post and article after article repeating the same misleading "fact" that you will get 6,000 or more hours of life from the CFL. Well, both consumer complaints and lab research are showing how untrue this is.
First, studies have proven what consumers have been discovering. CFL’s rarely meet their rated life in real world applications. Why? Well they may have been used in the wrong application. But they also depend on being turned on continuously or at least for 4 hours at a time to meet their rated life. If they are on for only 1 hour you get a 20% to 50% reduction in lamp life. If the CFL is used with 5 to 30 minute use cycles like most incandescents, the life is reduced 70% to 85%. That means your 6,000 hour bulb is now lasting 900 hours, less than many incandescent bulbs.
Second, the lifetime quoted on a CFL is just an average, meaning that 50% of the lamps can and do fail before the stated hours and can still be considered a valid rating.