I find it almost impossible to read the imprint on the needles - you need to hold the needle and the magnifying 'just so' in a strong light to 'just' make out what it says.
My trick - I have an old 'tomato' pincushion and on each segment of the tomato I wrote in permanent marker the sizes of the needles I use. When I take one needle out of the machine I put it into the pincushion in the appropriate segment; and I put a flowerhead pin as a place marker in the segment from which I took the needle that is currently in the machine. (Gosh i hope that makes sense). I needed a system since I switch needles at least once a day - I have made a commitment to practice my FMQ for at least 15 minutes every day - and I use a different needle for that than I do for piecing.