Step 6: Lighting
When considering what type or types of lights to buy, keep in mind the frequency that you will need to change them. Fluorescent lights last longer leading to less money spent over the long-term than incandescent lights, but offer no heat. Incandescents burn out faster, but also supply heat. Using the equation in step 4 will help to give you an idea of how much power you will use.
Also, decide on what will be safest for the animal. If the light has to be inside of the reptile enclosure, then consider fluorescent lights since incandescents can burn the animal if it touches it (like an iguana or a snake). If the light will sit on top and shine down, then an incandescent would work since there is no danger of the animal touching it.
Do not use regular lights from a hardware store! Reptiles use the light to help keep their bones strong and to regulate their metabolism. Specialized lights made for reptiles supply them with the proper amount of UV (ultraviolet) light that they cannot get from a standard light bulb. The cost of using a standard light bulb is great, because it will lead to vet bills and possibly the death of your pet. Look for lights that have acceptable levels of UVA and UVB rays for your animal.
For additional reading, you may want to check out this site:
It's an in-depth description of reptile needs regarding UVA and UVB light, and the types of bulbs that produce the best results.