We understand the system we have. Why change it? Those products that have changed, I think, have done so as a means of duping their customers into thinking they're getting more than they really are. When they changed from quarts to liters, they never lowered the price to reflect the lesser volume. In their heads, people think of the one-liter or two-liter bottle of soda as being 1-2 quarts. If we need an exact measurement of something, we can use metric because pretty much everyone understands that, too. Although their heads might think in ounces and quarts, most people can calculate in metric when they need to. It's not that complicated.

Restating what I said above, arguments for switching to the metric system in the US are more about abandoning the system of measurement that we all grew up with and understand than about adopted the metric system. For the past fifty years or more, everyone has learned the metric system, and most of us have used the metric system in one application or another, so we understand the metric system, although we may not think in the metric system. There's no need for a change.

I do agree with Ken as I learned 12, 36, 5,280 or 32 ,212 all these we had to remember as a child and now they have to remember 10. For us older people that still think in the way we were taught making it hard to make that change my mind still thinks in inches. Hard to teach an old dog new tricks.

The trouble with the base 10 is some may use it in the improper power of 10! Thus, some may say there are 100 millimeters in a meter, which is wrong by a factor of ten, or a Kilogram is 100 grams. See? Hal

That's exactly right. My mind is programmed to visualize inches and fractions of an inch, etc. When I see "15mm" my eyes glaze over because I can't visualize it (unless I covert it to inches) .

Ken, a Liter contains 33.8 fluid ounces. A Quart contains 32 fluid ounces. Therefore a Liter contains 6% more fluid than a Quart! Hal