This might be a silly question. I had been driving manual for quite some time before changing to an auto car. During traffic jams right we tend to place to neutral and put to gear 1 when the traffic about to move. Now my question was if an automatic transmission car during traffic jams should we place to "D" all the time while pressing the brake(which my mom always did that) or place to "N" when you stopped for quite some time and place to "D" when it is about to move? Which option will prolong the auto gearbox lifespan?

Because I heard some of my friends said don't always change from D to N, N  to D that often will easily spoil the auto gear box. I guess yeah...better put to "N" and not "D" when waiting for a long time and I felt the cabin got a slight vibration when place to "D" maybe because the idle rpm. Anyway thanks for the info. =)