"Roger Hayter" wrote in message
...
That convention certainly applies to science and engineering. And,
generally, in the UK we stick to it. But then we use cm rather than mm
very frequently (and make frequent errors in the conversion - see about
1 in 4 Amazon specs) and the French use dm as well as cm and mm. So
the convention does not seem to apply to daily life. We don't use dm
much, though. But we are much more likely to use tens or hundreds of cm
rather than 100s or 1000s of mm.

The exception to this rule of "1 - 999.999 x 10^(multiple of 3)" is the
gauge of railway tracks which is always specified as 1435 mm rather than
1.435 m (assuming it's not referred to as 4 ft 8 1/2"). Presumably the
over-riding principle is to avoid the need for a decimal point. There may be
other examples in civil engineering where this is done.