When it comes to naming things..

Say there's one name that a lot of people use for one planet, or animal, or whatever. Will that thing's name then be followed by a number, indicating that there are other things called that? Like I know a lot of people are going to name planets "Hoth" and "Naboo" or "Steve". Would those planets then be named "Hoth IX"? Or can planet or animal names only be used once?