I don't think they last much longer than incandescent lamps. I have two out of 4 in my bedroom light fixture that are out. Time is passing quicker these days, but I am almost sure they are no older than 3 years.
I had major surgery in May of 2002. I know it was months after that when I replaced them.
At least they are better than marriages - those are supposed to "last a lifetime".
Great guilt is weighing on my soul as I have been slowly but surely swapping out all the low energy lamps in the house with good old fashioned incandescents. A whole iceberg is prbably melting at this very minute because of me. But lights should come on, and come on full, when I turn the switch - and not look like a dying glow worm for the next ten minutes before finally getting bright enough to worry a whale-fat candle.
The spots where the fluorescent striplights were in the kitchen now have arrays of halogen spots. So I can wash and clean a lettuce without missing insects the size of dormice. I can measure ingredients without having to read the markings on the side of the measuring bowl as if they were Braille...
The number or years they last depends on the duty cycle, and if you leave them turned on more, they burn out faster. Regardless, you can't get a regular incandescent lamp to last for three years unless you simply don't turn it on at all!
Well, I have them ALL over the house. Now that they are making smaller (physically) sizes, I have put them in some fight fixtures including the "schoolhouse" globe for a ceiling fan.
In the "worse" application, I have the in the kitchen ceiling fan light (5 bulbs) fixture that happens to be controlled by a PIR proximity sensor. That means it goes on and off quite often. I'm guessing but it think I replace a CF in that fixture every 4 or 5 months or so.
In other places (the basement, windowless "pump room") I have a CF on 24/7. The 24/7's seem to last about a year although after the power goes out they seem to fail shortly after things come on again.
I have about 25-30 CFs used here. EVERY interior standard base with the exception of desk lamps and some decorative bathroom mirror lights is a CF.
I have had "bad batches" where they didn't seem to last long. "Lights of America" was the worse. But lately they seem to be reliable. They don't last "Forever" but subjectively they seem to last 2 or 3 times as long as "regular" lamps.
Try a different brand. I tend to buy mine from Wally World and I am guessing they have some quality control over the manufacturers.
The only negative is that when you first turn them on they are a little dim. It takes a minute or two for them to warm up and give full light. The bathroom mirror lights (mentioned above) are also on a PIR sensor and I get "instant on" with them.
Go back and try some others. Some of my early ones had short life and long 'turn-on' times. But the newer ones come on to full brightness very quickly, and last quite a while.
The ones I have in 'can' fixtures in the bathroom come on instantly, and have lasted over six years. One set I had in the kitchen didn't do so well, they only came up to full brightness after about 30 seconds, and they didn't last three years (they are inside a globe fixture, so I think the heat builds up).
Keep your receipts! The 5 years is a promise the manufacturer makes, not the gospel truth handed down from on high.
Fluorescents of all types simply work differently than incandescents so they will respond to use in different ways. A> It is usually the starting process that fails so their "life" rating is based on 3 hours for every time they are turned on. B> The screw-in kind are VERY different from one manufacturer to another and from model to model and sometimes even batch to batch. (See #1 above) C> If you use them upside down (like in a can light,) their delicate and cheap components (See B above.) are heated by the light itself and are usually not intended to be so hot. So read the fine print on that promise. D> Newer lamps are better made than those of 3 years ago. Just because those failed doesn't mean the next ones will. In fact you probably can't even find *exactly* the same ones for sale. (See B above.)
And of course we will all learn this all over again as LEDs become more common.
Mnay of these compact flourescent lamps that have large words saying "5 years" also have fine print saying something like this lamp is expected to last for 5 years if used for 2 hours per day. Make sure to read the all the package when you purchase more.