In all honesty I don't change the needle every-time, and will inject 4-5 times before changing. This isn't ideal, and I would advise those that are newly diagnosed to change the needle after every use. The lancets I will change every other day or when it feels blunt, but again it is wise to keep good practise from the start and change the lancets once used. Not sure if my slack procedure to changing needles and lancets stems back to when I was first diagnosed nearly 30 years ago, but given the small retail cost of such consumables as needles and lancets, there is really no excuse not to change them after every use, anything else is just lazy and sloppy!🙄 Toby.