From the manufacturer: These tabs have approximately 2 years shelf life after put into service (taken from the manufacturer's packaging). We have reports from many customer who have had these last 5-7 years. Keep enclosed tightly when not in use to extend the shelf-life. Just place in a resealable bag.
Important note: These are genuine Beadsmith Shinerite tabs. For some reason, there is a line of text on the back of this package that has been marked out. They've been coming to me that way for over a year. I am a registered Beadsmith reseller. These came directly from them.
These are the newer version.