Also, in addition to what Caleb said, you should probably avoid housing Males and Females (or two Males) together because of aggression issues. Males can get territorial, but then so can females, so placing them in a cage can elicit some pretty nasty behavior. Some geckos get on well enough, but it's best not to stress them out. Especially if you're not looking to breed them, yes.
I like to keep leos in groups, usually one male to 2 - 4 females. But, then I have alot of leos.
Leos will live very happily alone. They don't need company!! But living in groups will need to be adjusted due to different personalities. I've got one female who won't tolerate any other females with her. It just depends on the individual animal. Best to plan on keeping them separate if you don't plan on breeding.
I have 2 females who live together with no problems, but the rest are all separated in their own enclosures. I know people who keep 3-4 together in every enclosure. You just have to watch and make sure they're all getting enough food and none are getting bullied. They also need to be around the same size. I had a male/female breeding pair together and had to separate them because the male was taking all the food.