Best Method for Realistic Lights in N Scale Buildings - Model Railroader Magazine

I model in HO, but for this question there is little difference.  Bulbs are bulbs, LEDs are LEDs, volts are volts and to get to your question, amps are amps.

I use 16-volt incandescent bulbs from Miniatronics.  I like the warm glow of incandescent bulbs, and the uniform light distribution they provide, for my Transition Era layout.  LEDs are much more efficient, but their light is more white and blue, in general, and LEDs typically form a beam of light rather than a sphere of illumination.

I build an interior structure for most of my buildings:

This one is more elaborate than most.  I built a grid of rooms for this hotel, and put in a total of 6 lights, not all visible here.  This let me light up some rooms and leave others dark, which always gives a more realistic effect.

Although these are 16-volt bulbs, I run them at 12 volts.  This gives a softer, warmer glow, and greatly extends bulb life.  It also produces less heat, which I've never had a problem with but it's worth considering anyway.  Each of these bulbs takes about 30 milliamps.  When looking at a power supply, the current rating in amps is what you need to consider when deciding how much you can do with it.  I could run 100 of these 30 milliamp bulbs with a single 3 amp (3000 milliamp) supply.