I don't think we need to CONVERT to metric at all.

I know a guy, he's a helo pilot in the marines, he's also a major computer geek. He's been to Iraq a zillion times....

We were chatting about stuff, and he mentioned that he had to walk 12 kilometers in the desert in iraq, and it was miserable - I asked him, "How far is that?" and he said, "I just told you, 12 kilometers. Don't convert, just learn how long a kilometer is, and leave it at that."

That's when I realized that it's CONVERTING to metric that's the problem - so don't. Some things are metric, some aren't. That's OK.

I already have a few "everyday" metric moments:

9MM - I know that one!
5.56MM too!

1 Liter of Soda, 1/2 Liter of Wine

The bolt on the bar of my chainsaw: 12mm

I admit that distance is still not so strong for me. I really don't "know" what a kilometer feels like to walk, compared to a mile.

I would prefer measurements in milimeters, especially since I'm currently remodeling a bathroom....

Let's see, the 2x4 is nominally 3-1/2" but these are actually 3-7/16" deep, the wallboard is 1/2" and then a 1/4" mortar allowance, and a 3/16" thick, tile, the valve needs 11/16" projection from the finished surface, and sets back from the edge 2x4 1-5/16", so what time is it in London at noon?

Do we really need a faucet for this tub?