At least one of your two hides should be a humid hide. This is easiest on the warm side because the heat helps make it more humid in there three hides would be nice, but the minimum is two.
In a leopard gecko enclosure you would need:
Two hides(one on warm one on cold, one being a humid hide) a third hide as humid hide works
a bowl of calcium(NO D3)
A bowl of water
and that's pretty much it. I TOTALLY recommend an escape proof mealworm bowl. It's always great to have mealworms available at all times. Especially with young geckos who need to eat lots. Also feed crickets at meal times and don't forget to sprinkle (often with pure calcium, occasionally with calcium+D3 and occasionally with vitamins)
It's easy to dust the crickets. Shake and bake is the best method (sprinkle some into the bag, shake it up. Instant dusted crickets)
It's helpful to have a small kritter keeper to keep crickets in to let them get gut loaded before feeding. Just put a slice of potato and carrots or something in there to feed them.
And of course always have a thermometer to check the temps, make sure your heat sources are regulated and all that~
Yes, you'll need three hides and the better for your gecko to choose as he/she desires. The humid hide is a must, it aids for shedding and reduce the stress of getting stuck from shedding. Without it, he could have dry shed & lose some toes.
First hide are for warm spot which helps the digestion.
Second hide is for cool spot if it gets too warm.
Third hide, which is the humid hide... it's a must and whatever he's ready to shed, he'll use it to aid the shedding.
Okay. So what I have planned out for my future leopard gecko is as follows:
A 20 gallon long terrarium with screen lid
8 watt UTH (and my room is always hot/warm)
2 digital probe thermometers
meal worm bowl
calcium with d3