just a quick question, cooper you say to replace every 12 months? i though it was every 6 months? it says 12 on the packet but i always just replaced it every 6... just a concern because as much as i don't want to sound stingy every dollar i can save counts. ThanksCooperDragon":gclvrgwr said:I don't know that it's worth getting too mad over. The output is still pretty darn good and can easily get within daylight basking levels when set between 10-16'' over the basking site. Not knowing the decay, I'd stick with the rule of thumb to replace the bulb after 12 months unless you find a local reptile shop that may have a Solarmeter to help you test the output of your specific bulb.