The idea behind the red bulbs was that reptiles couldn't see the red spectrum of light. With this in mind, the idea was you could have the red light on all night, keeping them warm, but not keeping them awake.

It's pretty well accepted to be false now, as there wasn't any research to back the claim up, and research has shown that reptiles, while they see things differently than us, are capable of seeing color and lights (If you watch TV with your dragon, you might notice him watching it with you).

So unless you give your lizard a really nice place to hide out of the light, it will keep them from sleeping well. Think of it like if you slept in a room with the light on each night. You might be able to sleep, but you might not sleep quite as well as you would with the light off.

As far as red lights in the day: in my opinion they're just colored lights, and I'm not aware of any long-term effects from having them as day lights. But they won't give off any UV light, and they won't give off enough heat, so they're effectively useless to have.

For a bearded dragon, you will want a good UV light that's meant for desert reptiles, and a good heat lamp that will keep the basking side at about 100 degrees fahrenheit. Personally, I use ReptiSun 10.0 lights ( the straight tube not the coils), and a normal 100 watt light bulb for my basking lamp.

Note: This will be true for most, if not all, lizards, but not necessarily for snakes and possibly turtles, as their eyes are different.