Perma-Shave

The hero finds
Despite his trouble
He never has
To deal with stubble

Heroes have hectic lives, often taking them to strange places for days or weeks on end as they go on their adventures. However, they rarely get the opportunity to shave or clean up between car chases and explosions... and they still somehow manage to keep a baby smooth face!

Somehow these guys manage to find the time to get out their shaving kit (or an electric razor) and clean up after being put in a dungeon and before escaping from The Dragon. Of course, this can be Played for Laughs by implying the character just doesn't grow facial hair at all. While everyone else has a Beard of Sorrow-type growth from the circumstances, he is as smooth as a smarmy preteen or smug elf.

Of course it's just as commonly Justified Trope as the character being both Crazy Prepared and so dedicated to maintaining his personal appearance he always shaves (often before everyone else woke up). If he ever should stop shaving, it means he is suffering some kind of emotional breakdown.

While this trope is the Opposite Tropes of Perma-Stubble, both can coexist if the stubbly hero has a Bald of Awesome.

Not to be confused with Burma-Shave.

Examples of Perma-Shave include:

Literature

In The Hound of the Baskervilles, Sherlock Holmes has been secretly living in a stone hut on the moor for several weeks, and yet "he had contrived, with that catlike love of personal cleanliness which was one of his characteristics, that his chin should be as smooth and his linen as perfect as if he were in Baker Street."
In Starship Troopers, Rico notes that when Sergeant Zim is waking them up at insanely early hours he has a clean shaven face and otherwise excellent hygiene.
In the Doctor Who Eighth Doctor Adventures, it often seems that the Doctor doesn't need to shave. He grows an oddly sinister beard in one book, and other characters think he probably grew it just to see if he could. Even though his companion Anji repeatedly complains about how ugly it is, he keeps the beard for a few more books; it seems like he's impressed with himself for having grown it (note that in his shirtless scenes in his only televised appearance, we got quite an eyeful of his pretty, hairless chest; it may be no wonder that he's not sure if his follicles ever hit puberty).

Live-Action TV

Sheldon in The Big Bang Theory, more or less. When everyone comes back from the Arctic at the beginning of season 3, everyone else has massive full beards; he has a tiny, neatly trimmed goatee.
- This reflects the actors, Jim Parsons naturally has a very light beard but regularly ALL of the characters are well groomed. In between season breaks Johnny Galecki (Leonard) is usually sporting at least some stubble, to the point you barely recognise him as Leonard.
Glee: Kurt Hummel is, naturally, incapable of growing facial hair.
The Doctor has mentioned shaving a few times, and grew an epic beard while being held in Area 51, so he shaves at some point, no one just knows when.
- The Tenth Doctor straddled the line between this and Perma-Stubble, he never had enough to detract from his boyish good-looks, but he also looked like he hardly ever touched a razor either.
An interesting female example that shows you should take the term "reality" show with a grain of salt, the women of Survivor. The men will develop a full Jesus beard while on the island, but most of the women tend to stay fairly smooth-legged throughout.
In one time-travel storyline of Dark Shadows, now-human Barnabas Collins is chained up for at least a few days. Every time the story shifts to him, not so much as a whisker is visible.

Web Originals

Referenced by Yahtzee in his review of Left 4 Dead.

"There's also an office worker-type who doesn't seem to need to shave."

Hartley on I Am Not Infected. After a month without razors or other means to shave, he is completely clean-shaven whereas Paul and Charlie sport pretty good beards. Of course, they make fun of him for it, doubly so when he puts on a fake beard.