Every time I come across a thread about light bulbs I always see every one claiming this brand is the best and this one has the highest out put of UV and so on. There was a discussion on this forum about how much UV a tort really needs on a daily basis and it got me thinking. I understand that some brands of bulbs might last longer (how do you really know it is still putting out UVB?) but as long as the bulb puts out some UVB wouldn't that be sufficient? As long as it's on everyday for a certain period so the tort can soak up some rays, wouldn't it be sufficient? And if it is not sufficient, despite what the people say about their own product, how do you know if the bulb is still doing its job? I know most people say the bulbs are only good for about 6months then they are pretty much dead, but do they put out ENOUGH rays for a year. I stress the word enough because when a tort is outside in the shade it is still getting UV rays but its not the same as if directly in the sun. But that is still enough for the most part. I am not talking about heat at all, just UV rays. I would love everyones input, please