Since leopard geckos are naturally from the middle-east, you will need to make sure their light cycles mimic the same cycles as their natural environment. This means in the summer they should have 14 hours of light, followed by 10 hours of darkness, and in winter they need 12 hours of light and 12 hours of darkness.
What light is best for leopard gecko?
Generally, 5 to 6% UVB lights are perfect for leopard geckos. It is best to get a made-for-reptiles UV light as they are designed to output controlled amounts of light and UV radiation. Most UV bulbs are fluorescents, though mercury vapor bulbs also emit UVB.