Not sure if I remember right that the ink was changed in some markers, fumes too much for school use.
Anyway I have labels from years ago ink is still good, I replaced some last year, new pen, new tape, and they faded in 6 months.
Aluminium tags are good as it is indented even with a pencil pressed hard, no ink to fade. Same for UV stable plastic labels, you can scratch it in with a sharp nail.
I have had a moments of trying to decipher codes on some labels I wrote, it usually comes back a few days later.