I had posted another topic and asked how to test to see if thread is strong or past its useful age. I'm followiing the test where you pull out some ot the thread, wrap it around your fingers and tug pretty hard to see if it breaks.

Well, surprisingly, I started with some thread that I've purchased in the last six months. Out of 10 spools, I have found 6 of them that broke easily. 5 of them are the same brand, all purpose thread and in the same color range of navy!! I know darker colors are sometimes weaker because of the dye but was really surprised to find the newest threads broke so easily.

One of the spools is a more expensive brand of 100% vsicose rayon 40wt touted to be shiny, silky, strong, washable and dry cleanable. This spool was recently bought to see if the more expensive thread worked better.

I'm at the point where I want to throw the whole drawer full out!! :(

I've done the thread strength test as well with several of the threads I own. I don't know how reliable that is--I've had very old thread withstand some serious tugging without breaking while some of the very new thread breaks quite easily.
So...is there a more reliable test for those of us with thread of all ages???

i'd write or call the thread companies and say i had some of their older thread and wanted to make sure it was still usable. i would not say it was hundreds of years old, maybe two years, and certainly don't tell them you're testing against other brands.

see what they say. remember, they want you to buy new.