I don't understand why you do this. If you leave it in drive the engine will actually assist wth braking. Even an automatic transmission will provide some drag to help when slowing to a stop. Without the added engine braking you are working your brakes harder to bring the car to a stop and this could result in reduced life of your brake components.From the manual: Do not shift into N when driving the vehicle. Doing so can cause transaxle damage.
Is this an issue at low speeds? It's standard practice for me to shift from D to N as I'm slowing to a stop (red light).