​Maybe you think no one notices the bald spot where you over zealously trimmed your beard this morning. Or  cares that you used enough hair gel to seal the bricks in your fireplace. But someone does — and he'd like to tell you about it. Meet your long-suffering barber: The man who bears the brunt of your amateur-hour grooming aspirations. In fact, your barber has seen more grooming bloopers and styling gaffes in his years of practice than you will (hopefully) encounter in your lifetime. "As a third generation barber who has been cutting hair for over 20 years, I've pretty much seen everything," Greg Zorian, owner of Gregory's Barber Shop in Albany, NY, says. It only makes sense then, that if you want to know what not to do to your hair, he's the man to ask. “The short answer is, if you're not sure whether you should do something to your hair, you probably shouldn't," he adds. Here, seven cardinal sins of grooming ye shall not commit.

The Dry Shave
You overslept. Your meeting was bumped up to 7:30 a.m. You are in a hurry. None of these unfortunate occurrences excuses you from attempting to remove your facial hair with nary a shave gel, foam can or, for God's sake, plain old water in sight. What happens to your skin when you dry shave? "Oh, it's bad," Alexia Saras, barber manager at Fellow Barber in Manhattan, says. "Dry shaving causes ingrown hairs, rashes, and skin burns. You really don't want to go there." At bare minimum, you need a pre-shave oil, she says, to soften the skin and help the blade glide smoother over the surface. "Then, follow the oil with light shave cream that you apply with or without a brush."
 
The Goop du Jour
The hair on your head weighs, at best, half an ounce. The pomade in that jar?  Five to ten times as much. So simple math would suggest that your hair can't hold much product before it looks like crap. "You’d be surprised the guys who just dip their hand in the jar and put it right on their head," Saras says. "The specific amount you use is going to vary depending on the product and your hair type, but as a rule, always start with less than you think you need. You can add, but you can't subtract once it's in your hair." Also, work up the product in your hands first until it's smooth, so there are no big chunks going right into your hair. If you're still unsure, ask your barber to demonstrate. "I always show my clients how to apply it," Saras says.
 
The Self Trim
In most towns, you can get a barber to cut your hair for about 20 bucks. That's a beer and a burger at your local pub, or a few cups of coffee at your overpriced espresso joint. So why must you insist on grabbing your kitchen scissors, or beard trimmer, and attempting surgery yourself? "Proceed at your own risk," cautions Charles McCoy, master barber at Kiehl's Barber Shop in New York. "You may find yourself with patches left over and a poorly finished head of hair." What’s that? You're just trying to even out your neckline? "I have a friend who sees a little hair on the back of his neck and grabs a razor to 'fix' things," Zorian adds. "From the front, it looks okay, but what he can't see is the little tail he leaves in the back from the spot he missed." Worse, Zorian says, are the guys who turn their razors upside down and shave the back of their neck up into their hairline. "I'll go to trim it and there is a huge hold underneath the hairline from running the razor too high." At better approach: Pop into your barber shop for a trim every four to six weeks — unless you're going for a buzz cut, in which case "it's fine to do solo, as long as you understand the fundamentals of proper hair care," McCoy says. In other words, see a pro.
 
The Helmet Head
We get why you want your hair to hold its style. We don't get freezing your hair into a permanent state of hardness, so that your barber needs WD40 to loosen it up before your cut. "There will always be guys who use half a bottle of gel and their hair looks like it won't move for the next year," Zorian says. "You're not going to talk them out of it." For everyone else, a dollop the size of a nickel is plenty to start. "Rub it down into the roots, comb it through the hair, and let it dry," he advises. If you still want more hold after that, add a finishing paste to dry hair, not more gel, which will result in something akin to helmet-head. Another tip: Using a gel on overly-wet hair won't work, Zorian says, because most gels are water-based, meaning they dissolve in water and will lose their potency. Shower, towel dry, then apply. 
 
The Comb-Over
Everybody knows the guy who does the comb-over. You laugh about it, and wonder if he thinks he's fooling anyone. Then one day, you wake up and discover your hair is thinning. And in the midst of your premature midlife crisis, somehow you become that guy. "I have many clients in this situation," Saras says. If you find yourself caught between a comb-over and a bald spot, "covering it up is never a great option." Better move: Get your hair trimmed close in the area that's thinning (usually on top), and leave it longer on the sides — it will look fuller, Saras explains. The other choice: Shave it all off. Because at the end of the day, if you are going bald, all the clever styling and trimming in the world isn't going to disguise your predicament for long. The only thing that will: A clean shave that leaves people guessing what your hair might look like, if you had any. 
 
The Patchy Beard
It's not soul patches, but that hole in your beard that drives barbers crazy. "Most beards don't grow in perfectly even — some areas of your face will grow more hair than others," Saras says. You can try to spread the wealth of hair that you do have by using beard oil or mustache wax to smooth out curly areas, which can help cover thin patches, but ultimately, "this is a job for a professional." What your barber can do: "If the bald patch is under your chin, I will fade the beard down to that spot, so it looks natural," she says. "If it's higher up or on your cheek, we can move the beard line below the spot." The better overall care you take of your beard, the less likely you are to find thin patches. "Apply a moisturizer or beard oil every evening before bed," McCoy says. "It will keep your beard and the skin underneath in great shape."
 
The Brow Beater
Being aware of your unibrow is half the battle. (Barbers say many men sporting the single hairy strip do so in blissful oblivion — it's their significant other that sends them in for help). Ridding yourself of the caveman look takes practice. "If a client has just a few longer hairs, I will use a scissor-over-comb approach to even them out," Zorian says, who adds that he doesn't think eyebrows should look too perfect, but thinks waxing is right for guys who want shape. "Waxing is effective if you have a high pain threshold," McCoy agrees. For a more natural finish, he uses tweezers — "it might sting a bit but it's better than shaving, which can leave dark follicle marks between the brows, and hair can regrow with a vengeance."