Hey Earl,
I get what you're saying, but it really all depends on how many one buys and how long it takes to go through them. Definitely do
not buy batteries in bulk if you don't go through em; truth! But I do. If a gig depends on it, the guit gets a
new battery regardless of the voltage. And I do check the voltage later when I get home to determine whether it gets tossed or saved for sound checks ...or whatever do-dads may need a 9v. Ahhh, the beauty of an ES where a batt change takes
seconds. Clearly I cannot do this with the guits where the batt is inside, so with those I am more fastidious about checking voltage, keeping unplugged, or replacing proactively (especially the 12er since that guit gets goes a
very long time between few string changes and so I plan out that batt change). But absolutely with any equipment that must work without fail (e.g wireless handheld mics where we changed the batt
every time because you
can't ever have a dead mic!)
So yeah, your point is well taken.

Edward