The metric system (SI) is awkward to use in some common cases because it requires more digits than Imperial for common precision or range. First, consider temperature. Indoors, 20C can be too chilly, 21C too expensive to heat, and 69F just right. Outdoors, 33F is still above freezing, but the equivalent 0.6C is cumbersome. Next, look at speed and length. On a limited access highway, 100Km/h requires three digits, yet in miles per hour all posted speeds in the US require only two digits. Ten inches spans many more everyday objects than 10cm.