Putting them in the freezer before they are depleted will stop (or very much slow down) the degrading of their glow properies once activated. It also tends to “kick” them back up a little bit.
The longest I ever left them in the fridge was about week so I don’t know if they will stay “in stasis” (when frozen) longer than this. When re-warmed they pick up from where they left off.
astro, and anyone else reading, please: when you start a thread, please provide a link to the column you’re commenting on. Helps keep us on the same page, and saves searching time. Yeah, it’s on the front page at the moment, but will soon vanish into the bowels of the Archives and be harder to find.
Of course, over here in Europe we can use Tritium light sticks, with a 20 year lifetime. I understand that they are banned in America in case someone wants to use them to make a nuclear bomb.!