I have a 18'' uvb bulb and i remember when i first got it that it said to replace after 1 year. Its been about a year now and I am wondering exactly how long these bulbs last. I don't know if the manufacturer lowballs the expected life to get customers to buy new ones on regular intervals. Can anyone give me advice on this. I don't want a bulb that is decreased in its ability to give adequate uvb to my cham. Thanks!!