Guess what else I found?

My old "PSION 5 mx".  
I seriously have NO idea when I last used it - BUT - I can guarantee it was "Before Alice".  SO - it's a bare minimum of five years. 
I've taken to thinking somewhat along "B. C." & "A. D." lines.
The "Before Alice" refers to any time pre - 21:00 Monday 5th Dec 2016
After Alice being any time since.  Yet more gobsmacking - I recently ousted a dead cordless Mouse much younger, NOT because of the battery corrosion, which there was, but because it had been pensioned off some years go and never jettisoned.  
"Quelle belle Surprise" = two virtually un-corroded AA Cells. 
Replaced >>>--------> It works. 
I suspect it'll need a new CR 2032 as it had reverted to 01-01-1999.