A week or two ago I got some liquid to clear the algal growth on the inside of the fish tank. You had to calculate how many drops the tank needed. In metric the instructions were “multiply the length width and height of the tank (in centimetres) and divide by 1000 to get the number of drops needed”. In Imperial the instructions were “multiply the length width and height of the tank (in inches) and divide by 279 to get the number of drops needed”. Have you ever tried to divide 5340 by 279?
Meanwhile, after the School Wine and Wisdom, a couple of (ageing) engineers were singing the praises of the old Imperial measure (they'd previously stayed up until 2am discussing whether a litre was the same as 1000cc). This new argument ran along the lines that quarters, 8ths, 16ths, 64ths, etc, were better than stupid millimetres because they could be multiplied by more things (2, 3, 4, and 6 rather than just 2 and 5).
So, here is the official engineers guide to measuring small things in Imperial.
Half of a whole is 1 half (so a whole is 2 halfs, or halves as they're known). Half a half is 1 fourth (so 1 half must be 2 fourths). Halving a fourth you get 1 eighth (so 1 fourth must be 2 eighths). Halving an eighth you get 6 teenths (so 1 eighth must be 12 teenths). Halving 6 teenths you get 30 tooths (so 1 teenth must be 10 tooths), and halving 30 tooths you get 60 fourths (so 1 tooth must be 4 fourths).
Accordingly 1 whole = 2 halfs = 4 fourths = 8 eighths = 96 teenths = 960 tooths = 3840 fourths. So, unless I've gone wrong, stick to millimeters - without them the mileometer on you car wouldn't work, would it?