on shaving in the military

Shaved heads were standard in the Roman army and some others to prevent lice. Long beards can interfere with helmet chinstraps, so that was a reason to shave. Later, short mustaches were favored because anything else made it impossible to seal a gas mask. If you've ever wondered why Hitler had a mustache like that, it was from the gas mask he wore as a soldier in WW1. 

Sideburns were named after Union general Ambrose Burnside. Many other famous generals and presidents had facial hair including Lincoln, Grant, and Teddy Roosevelt. Burnside's facial hair would be a no-go in today's Army. 

I never liked shaving with a razor. It was one of the many nuisances I endured in the Army. Various exemptions are possible for medical and religious reasons. I knew one soldier who got a religious exemption for being a Norse pagan. I had a mustache for most of the time I was in the Army and I shaved my head with clippers once a month. 

If clippers are good enough for head shaving, they're good enough for face shaving, and such a shave will not cause any ingrown hairs or other medical issues. Half a millimeter of stubble is not going to affect the seal of a gas mask, and US soldiers have not faced poison gas in battle for over a century.

The fashion show aspects of the military get tiresome quickly. They rarely serve a practical purpose and get a disproportionate amount of attention. The same is true of physical fitness standards. 

 

I look forward to a day when practical considerations take precedence over personal preferences.