I think if one collects one thing, they probably collect others as well. We probably have a stronger "hunter gatherer" instinct than others who don't collect.
I know I have to rein myself in when something else attracts my eye, because I can't afford to be collecting too many things at one time, nor do I have the room to store much more "stuff." So for example, I collect the JC charms, but I limit my other jewelry purchases to only charm related items, because I like to make jewelry so already have more than enough.
Also I'm the type that once I have something, I never want to let it go, as in sell something to buy something else. I'm always amazed when someone gets bored with their charms and then sells them off.