There is no specific shelf life for thread. Thread like fabric does get weaker with time, but not all fabrics or thread age the same. The test for thread is to reel off a bit and try to break it with your hands. If it breaks easily then throw it out but if it is hard to break it is still good.

But you need not throw away those old wooden spools - lots of crafters use them for cool projects - for instance....

{{!gwi}}

Here is a link that might be useful: vintage spool peg racks

I don't throw away ANY spools. My mom used to save hers, and when my daughters would go visit (as toddlers and preschoolers), they would play with them - - roll them around, build things with them, stack them up and knock them down - - it kept them busy and their little imaginations going for HOURS! I'm not sure what happened to Mom's bag of spools now, but I'm saving mine for one of those same daughters who has become a preschool teacher.

Donna

As long as the thread was stored correctly away from sunlight and normal environment it should be good to use. I have used some that came in a treadle machine I was given. Save the spools beside children, cats and dogs love them too.