The needle manufacturers say you're supposed to change it every 8 hours. But that's actual sewing time. I know I don't change mine quite that often but I do change it pretty regular. Since I have several types and sizes of needles I bought a plastic organizer thing that's just the right size to hold the needle packages. I think it's supposed to be for beads. Anyway, I put a button in the space that I take the needle out of. If I use a needle but it's still good I put it back in loose and that way I know it's still good but not brand new. The different color buttons in the box are for different machines.
My goodness. You sure are organized. Wish I could say the same for myself.