Americans: go pick up the closest consumer packaged good within reach. You will find it is labeled with metric.

It would be nice to get highway signs in both units, though with Google maps obeying whatever’s selected in your settings, that matters less than ever. Some woodworking stuff is just too far gone down the imperial hole and will never come back. But other than such odd niches, you can live a metric life in the US without much trouble.

And drugs!

And 2 liter bottles of soft drinks.

Some bullets if they are nato standard or originated in europe. But other wise it can be based in inch or how many round balls you can make by dividing one pound of lead

Many videogames are in metric too. Battlefield and many other games use it.

No? Caliber is based on the inch

That's great and all. But by measuring everything in millimetres and grams you miss out on the very thing that makes the metric system great; the easy conversions. You can measure things in millimetres and easily switch to centimeters, just by moving the decimal sign, when the measurement gets large enough. That way you can almost always keep the numbers manageable. No need to say 1500 millimetres. Just say 1,5 m.

I still like the feel of feet/inches for length, but grams are way, way better for cooking and meal tracking.

Celsius is pretty easy. You probably like 20c inside year round. The high teens to mid 20s are comfortable. 13c and below is quite cold. 25c and up is quite hot.

If you use a PC, your temps are probably 30-85c, which is an easy way to learn too.

"30 is hot, 20 is nice, 10 is cool, 0 is ice" is a good way to learn human temps.

My recommendation, just set your phone/watch/thermostat to C. You'll learn it within a few weeks of cutting over :)

90mm x 45mm is what’s available near me for framing timber. And yes it’s more accurate.

Millimetres in general are used heavily in construction, everything is stated in them, even into the thousands where people normally would have switched to metres.

Every time a Europeasant makes fun of it, we add a new kind of standard measurement.

(While the important stuff is done in metric)

Seemed to work fine everywhere else.

There’s mass confusion now. It’s why industry by industry is voluntarily metricating. Most famously American aerospace used US Customary until a conversion error crashed a Mars mission.