Exactly as all the others have said...till it doesn't work anymore! Then either toss or use for decoration (I like that idea, btw).

If I have some doubt I will use it to baste - applique, hexies etc.....

For as long as I can pull on it and it doesn't break. I still use off spools I've had for 20-30,years.

Me too I agree

If there are colors you know you won't use, be sure to just throw away the thread - and keep the wooden spool. They are so cool and can be used to decorate your sewing room. :)

As others have said when it becomes a pain by constantly breaking or shredding. The only thread I know with a short life is invisible thread which I was told lasts about 2 years . If the invisible thread snaps easily when you pull it with your hands the throw away.

I agree. I have some of my Grandmother's wooden spools (I'm 63) and won't throwaway those pretty wooden spools. I occasionally use it for hand basting.

Wish there was a like button. Great suggestion.

Tug-test! Anything that passes the tug test is probably suitable for machine sewing. Anything that fails is still good for non-critical hand-sewing; like basting or putting together mockups or adding decorative whip-stitching.

If the thread is terribly faded or really falling apart and on a wooden spool I'll strip off the thread and keep the spool. I find uses for them here and there. When I put cabinets into my sewing room I rustled up 10 small wooden spools about the same size, wound a layer of turquoise or orange thread onto each of them (my accent colors for the room), and used them as knobs for my cabinet doors! I love them!

Until spool is used or fails the tug test. Thread is expensive.