I saw a video online where someone said UV was beneficial for balls. This site looks as if it's made for kids rather than adult owners but I guess there are varying opinions...

Here's the site: http://www.reptilestv.com/video/snak..._python/00.htm

On the vid they say the balls have some kind of glands running down their backs where they produce something with the help of UV rays... I'm not convinced though. My balls have never had UV and they're doing fine.