DH, being a marine type, although not navy, had a beard off and on throughout his 20s and then went clean shaven in his 30s, and then did the reverse of Feetlebaum regrew one for an operatic performance, Princess Ida, I think.
The children and I agreed to this on the condition it came off as soon as the show was over, but when the beard appeared we all liked it so much we told him to keep it, which he did. A few years later he had to shave for a operatic performance - and we all hated the unshaven look so as soon as the show was over he regrew it and has had one ever since.
DS has a beard because, like me, he has very sensitive skin and shaving left his skin red and raw. He tried all sorts of different shaving creams, oils etc and razors but without effect so by his mid 20s he had decided a beard was the way forward, although it is closer to designer stubble than DH's carefully kempt beard.