While more recent AA Duracells are crap, and commonly leak everywhere, their PP3 9V still seem fine.
I've just changed one in a battery powered intercom I've had for a VERY long time, from attic down to kitchen.
Took it out and it read 5V off load, the bottom was slightly swollen, but the date on the side (which is a VERY long use by date) was March 2008 - so it's probably lasted over 20 years, but of course it's a very low usage. Modern AA Duracells often leak while still in the packet, at only a couple of years old.
I've just changed one in a battery powered intercom I've had for a VERY long time, from attic down to kitchen.
Took it out and it read 5V off load, the bottom was slightly swollen, but the date on the side (which is a VERY long use by date) was March 2008 - so it's probably lasted over 20 years, but of course it's a very low usage. Modern AA Duracells often leak while still in the packet, at only a couple of years old.