I'm not sure how class related this is but I was curious if the Army still had a height requirement and if and when it was abolished. I was looking specifically at the British Army simply because the history is longer.
Looking at the Army general regulations (specific regiments might have more stringent requirements) it seems there was a gradual decline in the minimum height requirement from 5'8" in the mid-1800's to 5'6" by the end of the 1800's and then a more rapid decline during the First World War - first to 5'5" then to 5'4" and finally to 5'3".
The demand for troops in the First World War ultimately led to the creation of special battalions in which the normal minimum height requirement for recruits was reduced from 5'3" to 5'.These were known as bantam battalions and recruited a large number of miners. It was the success of such battalions that probably led to the phasing out of the general height requirement.
It was around the same time (1916) that the British Army revoked the standing order that all military men were required to maintain a mustache. To be a bit more accurate the army didn't actually require a mustache it just forbade shaving of the upper lip....
There does not seem to be a height requirement these days, which makes sense now the army is less stabby and reach is less of a factor. Still, it's interesting to note that 200 years ago, when people were generally shorter, the army would have recruited largely from the upper end of the bell curve of height making a regiment of Guards (who had, and I think still have, a more stringent 6' requirement) appear massive.
Which brings us back to class and gives me the opportunity to link to this fascinating New Yorker article I mentioned: The Height Gap - Why Europeans are getting taller and taller-and Americans aren’t.