Accurate measurement is often the key to quality work, so sometimes I use a "story stick" and make a mark directly off the first object. I grew up with Imperial, and then my country went mostly metric, so there's a lot of wasted effort on conversions now, especially with the US next door. I absolutely detest the ambiguous "Gallon" which may be U.S. or Imperial. However, I still prefer working in inches, because what we really need is to calculate in base 12 in order to get pleasing proportions with whole numbers, or to use 60 symbols for everything. Sadly, the aircraft industry went to decimal inches for everything, so Boeings are as ugly as Airbusses, and NASA wouldn't have lost a Mars lander if the Imperial contractor had been writing out feet, inches, and fractions that couldn't be mistaken for metric.