[quote=@Tortoise]
Being the GM should exempt you from character sheets or smth.
[/quote]

Important Non-Player Characters should have a character sheet, for much the same reason players create character sheets - to remind them of their character's details.

Minor characters who won't be interacting much with the players should have a brief writeup if only for you to reuse them again. Like the Quartermaster's Assistant - Harold - This teen boy makes you think of a strutting cat. He has round chestnut eyes. His fine, wavy, neck-length hair is the color of varnished wood, and is worn in an unruly style. He is very short and has a graceful build. His skin is pale. He has a wide forehead and small hands. He wears a green beret, a tanned leather jerkin, a dark green peasant blouse, dark brown breeches, and a tanned leather belt with a small knife in a sheath. He's usually barefoot. He likes to flirt with the girls when they pick up their supplies.

Harold really doesn't need much more. Some will never get a write-up, good for a scene and gone.