I was just wondering if green laser pointers require a warm up time? I've bought 6 now and I noticed that either start out dim until I play with them for a while. Or they start fairly bright and if I play with them they get brighter. I do have one that the on/off button is extremely sensitive and will even turn in by the weight of the button itself but I start out super bright and doesn't flicker like the other 5 I have. Does anyone know why this is? Or is this normal?