I know that some of mine are from 1960 or earlier.
Some belonged to a deceased sister and it is hard for me to part with them. One has an old needle still in it that belonged to her. Both hers and mine still have thread on them. Someday someone will throw them in the trash when I am gone, but in meantime, they stay put on her thread dolly and in my thread box. No reason for keeping them except they are old and so am I.