If you don't plan on ordering anything with coins, then save your codes until the "Club Nintendo year" ends and your status resets.
If you want to get something (especially if it's something that can be removed from the shop, like the 3DS game cases or Golden Wii Nunchuck), then don't bother saving the codes, redeem them now, or as many codes as it takes to get enough coins to get that thing you want to order.
Opie & Anthony | Ron & Fez, XM 105/Sirius 206 XBL: Maxx the Slash | PSN: Maxx_the_Slash | 3DS: 3222-5637-7984 | Wii U: Maxx_the_Slash
Unless they're new games that I would get extra coins for from intend-to-but surveys and registering them within the first month of their release, I'll hold on to the codes and register them when strategically possible. I have an extra 3DS code sitting around and I don't intended to connect my Wii U to Club Nintendo until July. I also have several post play surveys that I'm waiting to use in July as well.
Want Luigi's Mansion: Dark Moon, Rayman Legends, and Bioshock Infinite. i7-2670qm @ 2.2ghz | 6GB DDR3 | 1GB Geforce 540m