For one leopard gecko, it is advised to have at least a 20-gallon tank or terrarium so that they have room to move and climb. When I had my leopard gecko I had him in a 40-gallon tank so he had the highest quality of life and didn’t get cramped. They also need lots of places to hide and climb. It is recommended that they have at least three places to hide, one should be warm, one should be cold, and one should be able to be dampened because that can help when they go through the shedding process. You should also put fake rocks, logs, and greenery for climbing, basking, and hiding. The next thing your gecko will need is heating and lighting. They need a UVB bulb for the daytime and a ceramic heat bulb for the nighttime. It is also recommended that you put a heat mat on the underside of the tank where the hide is on the hot side of the tank. The hot side of the tank should be 85-90 degrees while the cooler side can be 70-75 degrees. The UVB bulb should be turned off at night so that it is dark, since they are nocturnal animals they need to have darkness during the night. For substrate, there are many options like coconut fiber, mulch, aspen shavings, or reptile carpet. All of these are good options but they should be spot cleaned daily and fully replaced monthly. They will need a water dish as well for both drinking and soaking. When leopard geckos shed they sometimes need to use water to help loosen the skin. The dish should be large enough for them to fit their whole body inside, but not deep enough that it goes above their ears. Food can be scattered around their cage so they have to “hunt” for it, so they do not necessarily need a food bowl.