Mechanical pencils bypass the problem of broken tips, constant sharpening and give you neat, uniform thickness writing all the time.
A mechanical pencil (US English) or a propelling pencil (UK English) or a pen pencil (Indian English) is a pencil with a replaceable and mechanically extendable solid pigment core called a lead. The lead is not bonded to the outer casing and can be extended as its point is worn away. The pencil lead is made of graphite or a solid pigment.
Mechanical pencils are used to provide lines of constant thickness without sharpening in technical drawing and writing. They are also used for fine-art drawing. Mechanical pencils are also popular with students, since they do not have to be sharpened. Despite popular belief, mechanical pencil lead is (usually) identical to a traditional HB (US #2) pencil.