Wow, a lot of us are very innovative! I use a lot of the things already posted, but something else that I do is jot down on a Post-It note what type/size of needle I have in the sewing machine. I stick it on the side of the machine, and when I'm finished sewing for the day, I put the note under the presser foot and pierce it with the needle. That way I'm not always guessing what needle is in the machine (and also not having to magnify those tiny letters and numbers to figure it out!).