The only rule that I have is I don't want all kids to ahve the same fist initial, as I am just not in to that.
My DH has 52 first cousins, out of the cousins, we are up to baby 89 due in January, so there are many that have the same names.
My son is james. DH had an uncle James, a cousin called james, and there are 2 3rd generation James' so far.
Doesn't worry me in the least.