It has ceased to matter. Most new products sold in the US use metric fasteners. A typical family has little or no use for imperial tools. There are some weird hold-out standards such as spark plug wrenches, but those have only one use anyway.
The imperial units are all defined in terms of metric units. There's no standard inch sitting in a vault somewhere.
Machine tools can switch from one to the other in a jiffy. Most design drawings give both units.
There are some odd things that still come in imperial units such as building materials, but a "2x4" is anything but 2 x 4 inches. Plywood is imperial length, but metric thickness, rounded to the nearest convenient inch fraction.
Food still uses imperial units of measure, most of the time, but people just eyeball the quantities and probably don't even know the actual amount. Most people can't look at a container and tell you if it's a pint or a quart.
I believe what happened is that the metric system was taught as a bunch of math, and people hate math. The big push came while I was in grade school, and I remember being taught: "The metric system is easy, all you have to do is some math." Metric was math and conversion factors. I remember a machinist telling me: "I hate metric because of the math." Yet he could add fractional inches in his head.
The imperial units are all defined in terms of metric units. There's no standard inch sitting in a vault somewhere.
Machine tools can switch from one to the other in a jiffy. Most design drawings give both units.
There are some odd things that still come in imperial units such as building materials, but a "2x4" is anything but 2 x 4 inches. Plywood is imperial length, but metric thickness, rounded to the nearest convenient inch fraction.
Food still uses imperial units of measure, most of the time, but people just eyeball the quantities and probably don't even know the actual amount. Most people can't look at a container and tell you if it's a pint or a quart.
I believe what happened is that the metric system was taught as a bunch of math, and people hate math. The big push came while I was in grade school, and I remember being taught: "The metric system is easy, all you have to do is some math." Metric was math and conversion factors. I remember a machinist telling me: "I hate metric because of the math." Yet he could add fractional inches in his head.