There's going to be a change in the number of coins you get registering certain products on July 1.
https://club.nintendo.com/coin-values.do
There's a list of games and systems having their coin values dropped. If you have anything on the list I suggest you redeem them before July comes along.
A notable thing seems to be that some games have had their values INCREASED instead such as PilotWings Resort, Resident Evil Revelations, Pokemon Rumble Blast, etc.