Mechanical pencil wins hands down! The lead is so thin that it's always sharp.

Without the hassle of constant sharpening it works for long time.There is also no need to sharpen the lead always. Manufacturing does not require wood.And these are great and perfect choice for drawing and sketching.  They are easy available in market to replace at anytime. Without requiring perfect sharpness this lead can draw the lines with constant thickness. A clutch pencil will use thicker leads of which ranges from 2–5.6 mm diameter and generally holds only one piece of lead for one time. These Mechanical Pencils mechanisms use only a single lead diameter for life time.

The only downside is the cost though.

https://en.wikipedia.org/wiki/Mechanical_pencil