Do you mean credit unions? It wouldn't hurt you to belong to more than one. Some often are members of more than one. It just depends on your circumstance as to whether it is actually beneficial.
You're welcome. Do you have one in mind? A local one? If you are elligible for NFCU I would highly suggest them.
I've been looking into it myself, my father was retired from the DOD, so maybe I stand a chance.