I had a time where I went through several batteries and it went like this: First discover my meter doesn't work, so I change my battery, and everything works fine. I had noticed that my LED's appeared dimming and then thought it was just time because I was using my Leica a lot.
Then I discover the new battery is dead after a weekend. The spares were stored in my fridge, but I never considered that they might have a shelf life, and I begin to think I have a problem. Perhaps they were in my fridge for years.
I buy fresh batteries because all the old ones are gone and the problem hasn't returned. Since then I had my M6 totally overhauled by Sherry and my electronics got a clean bill of health.
I'd have to check, but I believe my Nikons use the same batteries as my Wetzlar M6, and although stored in my fridge I can't say how old they were.
Good Luck,
Cal