For the past 20 years at least, I've had recurring thoughts that a decent microscope could come in handy after a zombie apocalypse. I'm thinking something in the $200 - $300 range with maybe a USB camera in it.
I like to use a 30x jewelers loop to check things out sometimes to better see the nature of something, just so I can say 'hey, that's neat'.
But, what kind of practical applications would there be for a microscope after zombies destroy the enterwebs?
Looking for bugs in water samples is about all I can think of. But, if you filter or sterilize water before using it that shouldn't be a problem. And, I don't need another $2-300 boat anchor or paper weight sitting around.