I change my needle pretty often depending on the fabric. I put a small piece of scotch tape on top of my machine and write the needle size on it. So if I need to hem jeans I know to change the needle and the tape. Maybe next day I want to piece and look at the tape I know to change it. I then change the needle and tape again. Also I keep the "little used needle" by labeling the size and storing it for the next time I need it.