[glossary: “Lamp” = lighting geek for “light bulb”; CFL = “compact fluorescent lamp”]
The method for determining lamp life is an industry standard. They take a batch of the lamps, and operate them on a specified schedule (x hours on, and then y hours off, repeat), and wait for the lamps to burn out. The point at which 50% of the original lamps have burned out is determined to be the rated lamp life.
As you’ve noted, there are other things that can affect lamp life. Temperature is one of them; a lot of CFLs don’t like lower temperatures, so if you’re going to use the lamp outdoors, make sure it is rated for that. Some are picky about the way they’re oriented, and should not be hung upside down (ballast up), so they should be reserved for table lamp use. Some don’t like enclosed spaces, and should only be used in open fixtures. Unless you specifically purchase a CFL that says it is appropriate for use in dimming fixtures, don’t use your CFL in dimming circuits. I have noticed that, in general, CFLs are a lot more sensitive to power quality than incandescents. That is, if you live in an area where there are a lot of power surges, this will likely reduce the expected life of your lamp.
For those of you who don’t like the cool color of CFLs ---- you’re buying the wrong ones. (And I’m with you on that. I much prefer warm light. And if you’ve ever looked at yourself in a mirror under warm white and then looked in cool light, you would prefer warm white, too.)
There are CFLs that come in different color temperatures. I like to use http://www.bulbs.com as a reference, because they provide the gory details on every lamp they sell. (From their main page, click the “light bulbs” tab; from there, select a category of lamp you want to look at, and then select the link for the individual lamp you’re considering to get the complete specs on the lamp.) Look for the color temperature, in Kelvin. I know that it sounds counterintuitive, but a lower color temperature means a warmer light color. If you like warm lamps, shoot for about 2700K, since that will match the color temperature of a standard incandescent. (Cool white is usually on the order of 4000.)
bulbs. com also shows several varieties of bug lamps, for whoever was interested in them. (Disclaimer: I do not work for bulbs.com, and I have actually never bought anything from them. I do find them to be an excellent resource for researching lamp specs.) I’ve never used bug lamps, but I’ve had a client who said he just painted regular CFLs yellow and got the same result much cheaper — but I don’t know if I buy that.
Regarding the flickering complaint: that is more common on CFLs with a magnetic ballast instead of an electronic ballast.