Another obvious advantage is the longevity of a mechanical pencil. Provided you’ve bought the refills in advance, you don’t need to think about replacing your pencil when it has reached the end of its life. There are some arguments to suggest that mechanical pencils are more environmentally friendly, though this should be taken with a pinch of salt. While mechanical pencils do have the advantage of being reusable, most are made of plastic which is not as sustainable as wood.
How much should I spend?
On the whole, not that much. A decent and reliable mechanical pencil such as the Uni Ball Kuru Toga will cost you £7, and if value for money is your concern, you can get a set of four Pentel P200 pencils for £17.