On Fri, 1 Sep 2017 03:50:38 -0400, rickman wrote:

Six foot skis are very convenient, but 180 cm are not
so much.

Why do you think that is? Because that's what you are USED TO, of
course. If you told me you skis are "six foot" long, I would have no
clue if they were too long or too short for me. If you told me they
are "one eighty", I'd know right away.

If you told me they are 1800 mm long, I'd still know right away. If I
told you they are 72 inches, you'd have to think about it for a
second. It is more convenient to move a decimal separator than to
divide by 12.

Another example, PCB traces are still measured in thousandths of
an inch even when working with metric sized boards because the numbers are
much more convenient, i.e. 6/6 vs. 0.1524 mm.

You've got it all backwards. I would make that trace 0.15 mm, which is
much more convenient than 5.90551181 thousandths of an inch.

Obviously, the inch is more convenient when you choose an example that
is a nice, round fraction of an inch.

Your example uses a unit that is ONE THOUSANDTH of an inch. You can't
do that. The thousand (and the hundred and the ten) belongs to the
metric system. The imperial system uses halves, quarters, eighths and
so on. Your trace is roughly 3/512 of an inch if you were to stick to
your system.
--
RoRo