Hey Dip --- HE wasn't always a patient --- They showed his life before --- Like when he was in WW2, then at home with his wife he was fucking sane till them and he was some kind of federal agent
From the OP's previous post, and from your ongoing comments about this film (which I quite enjoy reading - no lobotomy), do we really know that Andrew was ever a detective, let alone lived in some idealistic, overtly fantastical, lakehouse [on a detective's pay]?
If we were to bring the whole narrative back down to ground zero, simply: there was an overworked man, an unstable wife, a man who neglects his wife not foreseeing negative consequences, children are murdered by the mother, the father finds his wife, and he kills her.
This whole plot (back story) could most likely have taken place in the city apartment.
Even inmates and mental patients were obligated to shave daily in the 1950's. You'd get in trouble with the school authorities if you didn't, so it would be instilled in everyone that they had to.
If that’s even true then Teddy clearly forwent that ‘obligation’ or the staff didn’t mind. It would even help his therapy if he can look in the mirror and see his old/true self.
In the movie Escape from Alcatraz which is set in the 1960's for example, the warden tells Frank Morris (Clint Eastwood) that he will shave once a day, shower twice a week and cut his hair once a month. Also in The Gauntlet (1977), Clint plays a cop who gets a warning from his boss for showing up at work and had not shaved. That shows what the general attitude society had against stubble in those days. Which is why if you look at movies from back then and photos of even working class people in that era, they were all clean shaven or had a mustache but were otherwise daily shaven.
Well, I guess it's not impossible that not all homes and institutions were equally stern then. As a rule, men did not shave every fifth day like they do today (if they don't have beards which are obviously much more in fashion today than they were in the 50's), but it was pretty much unthinkable not to do it every day. If you were a spit and polish white-collar Cary Grant type, you could even do it twice a day if you went out in the evening. Obviously not everyone looked as smooth as movie stars who often had make-up, five o'clock shadows were common, but one with a several days old stubble would be someone like Otis the drunk on The Andy Griffith Show. Not respectable at all.
^^ Razor ads, but still, they do reflect the era pretty well.
It does honestly feel like Leo just did not want to to give up his 2010 look for a 50's or a clean shaven one here. Similar to how Harold Ramis and Bill Murray refused to shave their heads when joining the army in Stripes. But hey, at the end of the day, it's just a movie.