The Tex System is widely recognized and tells you the thickness of the thread. Larger Tex numbers mean thicker thread.
Pay attention to directions on your project; some projects require a particular type of thread for the product to come out correctly.
The short answer is yes, but there’s no set date that thread expires.
Danielle is a DIY/craft/sewing blogger on DIYDanielle.com. She loves to write about projects that she makes for her small farm, her children, and her home.