I've been using the Exo Terra Repti-glo bulbs for a while. They are just so much less expensive than the other bulbs out there. The thing is I'm afraid that they are lower-quality or something. It seems lately a lot of mine have been burning out quite early in their lifetime, and this makes me wonder if the ones still working are actually emitting quality UVB. What do you guys think of these bulbs? I was also wondering what the difference between the 13 and 26 watt bulbs are? Do they just emit the UV farther or what? UVB is just such a confusing topic...And I want whats best for my animals!