I cut small rectangles of white flannel and write the type of needle on it (ironing freezer paper to the fabric back makes it easier to write) Then I punch a hole in a corner of the fabric. Used but still sharp needles are stored on the fabric piece when not in use and when I'm using the needle I keep the flannel piece on my thread holder (I forgot what it's called!) on the machine using the hole I punched. Not only do I immediately know which needle is in the machine but I also keep my needles well organized. Really helpful especially if you use lots of different needles for various projects.
Hope this idea helps someone! Happy New Year!