Most mechanical pencils never seem that reliable. The leads break after a month of jostling in a bag and then it doesn't work when you need it. This could also

Most mechanical pencils never seem that reliable. The leads break after a month of jostling in a bag and then it doesn't work when you need it. This could also just be because I used 0.5 and never thought to try 0.7 back when I was taking long paper notes daily, in the pre phone era.