You don't need to shift to N, when you press the brakes fully and the car isn't moving, there's no need to shift to N, makes little to no difference. Same token, won't hurt if you do shift to N.

But based on logic, the less you move the shifter, the less wear on your control cable and torque converter (since it has to re-engage when you shift to D again).

Personally, unless it's a long stop, I let it stay in D. If it's a really long stoplight stop or I have to park, then it goes to P + handbrake.