How to save billions of dollars.

[Jester]

See for yourself: gram.

From your link:

...a gram is now defined as one one-thousandth of the SI base unit, the kilogram...

Any of those you need to calculate, even in your head, means you don't really use the metric system. You use some metric units when they are convenient, and then use whatever is convenient the rest of the time.

This seems a touch stringent. Nobody uses the metric system rigorously, exclusively, and instinctively. But then, nobody uses any other system that way either. I know the distance from Edmonton to Calgary in kM, not miles, but I know my weight in pounds not kilograms. I know the distance to the nearest star in astronomical units ( ) and I know the torque of my car in a precise, unitless way - zero anythings, because I don't own one.

But, I use the metric system for most things. Much like your insistence about water not technically freezing at 0 or boiling at 100, it seems like a distinction which is philosophically sound, but has very little application outside of hard science. Just because it's not being used perfectly, doesn't mean it's not being used.

-Jester