from experience in years of driving, malaman mo rin when to stay in D and when to shift to N in a traffic stop, or in stop & go traffic. kung slow moving traffic lang i just use the brake to control my speed, no need to step on the gas. it is only when in really bumper to bumper traffic that i have to gas-brake-gas-repeat to maintain a few feet of distance from the car in front otherwise masisingitan ka.

one other reason naman i shift to N when in a stop is to minimize disk warpage. especially if you've been driving for a while and been braking heavily, the front discs can get very hot. so when you stay pressed on the brake on a long stop, nagkaroon ng uneven temperature distribution. also the pads, especially the stiction type pads, may deposit some residue that can get built up over time. so especially now with timed traffic stops, and you know there's still a minute or so you'll have to wait, i just shift to N when in level ground, and N+handbrake when you feel the car is moving. the rear brakes naman don't get that hot, be it drum or disc.

very very seldom din that i use 2 or even L. going to baguio through kennon road with four passengers and some luggage, D lang ako and doesn't even need to use O/D off. pababa naman, i only needed to use 2 on long downhills coz of slow moving vehicles, esp. trucks. otherwise, i can coast downhill on D with occasional braking with no problem.