It's actually quite important to delete old Java versions, and better to do it via the windows control panel (add remove programs) or via CC cleaner than using Java uninstall.
The problem with leaving them, apart from the use of space, is that they leave your computer open to the sorts of malware that many of the updates were supposed to deal with.
The best routine is to download the latest version (frmo the Java website), save it but not install it, remove the old versions, then install the latest.