I messed up. I am completely to blame for this. No one made me read the Casio User’s Guide. It was my choice. I was doing OK right up till the last page.
Both User’s Guides have a section on the very last page titled “Initial Battery”. The paragraph below this heading states “The battery that comes loaded in your watch when you purchase it is used for function and performance testing at the factory. This type of test battery may go dead quicker than the normally rated battery life as noted in the User’s Guide.”
My first thought was that many inkjet printer manufacturers do something like this. Some of them include print cartridges in the box with the printer, but they are so called “starter cartridges” that have a very limited supply of ink, less than what would be in a standard printer cartridge.
My second thought was that my battery powered G-Shocks have operated for a long, long time on these “initial test batteries”.
Do you think that this information in their User’s Guide is just some legal disclaimer because Casio cannot know how long a watch might sit in inventory before being sold? To me it seems unlikely that Casio would put a “test battery” CR2016 or CR2025 in their watches that would not be relatively equivalent to a replacement battery.