Sometimes I rename a villager if I don't like their given name. Other times I will rename twins or triplets. For example, I had a VV named Soda (the original name). She had triplets and I named them Fresca, Fanta and Tab. With that one, I was just having fun with the names. Also, if I have a duplicate name in the same age group, I will rename one of them just to keep from confusing myself.