Does thread ever get too old to use? If so, how old is too old?

If you pull on it and it breaks easily, time to go.

If you pull on it and it breaks easily it becomes basting thread.

Helpful info!

I always used old thread for machine embroidery, with good new thread in the bobbin, and tension a little less. Now I just throw it out.

Thanks. The thread I found at home is probably 25 years old. So, how long do you think quilting thread is good for...1 yr, 5 yrs???

It seems to me that if it's on a spool and it's been kept out of the sun, it should never go bad. What would cause it to deteriorate?

old thread frays out and gets your machines really dirty. Yes you can clean the bobbin area but in the tension area you really can't get in there. So I would not use real old thread except for hand basting or even hand sewing.

Some of my clothes are older than that, thread and all. :lol:

I use thread on wooden spools that date back to the 40's and 50's with no problems at all (not on functional quilts), so if your 25 year old thread passes the tug test, I'd certainly use it. You can unwind and throw out the outer layer if you have doubts. Your choice entirely, of course.

Same here, and I second the idea of unwinding and throwing out the old layer. I have some of my grandmother's old quilts--well used ones. The thread is fine; the fabric, not so good.