Concerning metric, I am not sure it really matters anymore. All of the world except the US, Liberia, and Myanmar use the metric system.

Here in the US, we have become a dual system forcing students, engineers, and scientists to learn both systems. The science community adopted the metric-based SI system years ago and is used in almost all measurements, especially those with international implications or distribution. The US National Institute of Standards (NIST) adopted the SI systems years ago. Even the US military has partially converted over to the metric system and routinely trains soldiers in its use. Most cars and many other mechanical systems are partially or wholly composed of metric-based fittings and bolts. Look into almost any mechanics tool box and you will find many if not the majority of tools to be metric.

There will always be adherents to the older system while telling us how difficult the metric system is. Maybe they are correct. Maybe it is easier to remember that there is 16 oz to a pound, 12 inches in a foot, 3 feet in a yard, and 5280 feet in a mile, or judge the difference between 7/16 of an inch vs 1/2. And the math to convert is such a snap.

That is so much easier than multiplying or dividing by 10 when making conversions in the metric system.