Curl stylist Christo says he hears the question all the time from his over-40 clients.

“They ask ‘Christo, should I cut it short or keep it long?’ ” says Christo of Christo Fifth Avenue. “They feel like they’ll look silly if they keep their hair long. I feel like it’s an old cliché that’s totally wrong.”

In fact, Christo, like many stylists, believe there should be no rules when it comes to hair length and age. What is important, they say, is to find a cut and color that flatter the face shape — whether it be a short silver pixie or caramel ringlets that cascade down the back.

“That’s a big advantage of curly hair,” Christo says. “If they look bad with long hair as they’re aging, maybe we’ll suggest they go shorter. But if they look sexier and younger with longer hair, we’ll keep it long. You can choose to go short when you want to go short — not just because you turn 40.”

Ouidad says she has older clients who run major corporations who wear their hair long and curly, while many younger curlies might prefer short curly hair.

“I don’t believe in age and length,” says curl stylist Ouidad. “We need to shake it out of our heads.”

“It’s about who you are and what you are and what works for you,” Ouidad says.

Hair does tend to change as people age. It may become thinner and the curl pattern may become different. Gray hair can have a wiry texture and can be more porous.

As women and men get older, their hair can become dryer, especially if they’re coloring their hair more often. That is why it’s more important than ever to condition the hair.

Deep conditioning every week or two is highly recommended, and the hair should be cleansed only every three to four days. Leave-in conditioners also are recommended rather than holding gels, which can be more drying.

Stylist Diane Da Costa, who recently wrote ‘Textured Tresses: The Ultimate Guide to Maintaining and Styling Natural Hair,” says a lot of women over 40 have been relaxing their hair for so long that they’re now looking for a more natural, textured look.

“Their confusion is how to achieve it, grow it out and still maintain their look,” Da Costa says.

She recommends starting the process by texturizing the hair to soften the curl pattern. That can provide versatility and help with the transition from straight to natural.

For older women who work, Da Costa likes to keep the hair long enough so they can pull it back if needed. She likes chin-length and shoulder-length styles because they provide that kind of versatily.

Lorraine Massey of Devachan calls her mature curlies her “silver sirens.” Like other stylists, she doesn’t hold to any rules when it comes to curl length. But if it is longer, she believes it should have a fun shape.

Christo likes to cut longer layers — with face framing angles — while keeping the length.

“By strategically cutting the hair to contour around the face, giving good movement, it allows you to look sexy with it long,” Christo says.

Color — whether to do it and what shade to choose if you do — can be an important decision for older curlies.

“As you become more salt and pepper, you can evaluate where you go with that,” says Rodney Cutler of Cutler/Redken Salon. “There’s no critical rule.”

For some women, silver hair can look fantastic with their skin tone. For others, especially those with darker hair, it can make them look older than they truly are. Sometimes coloring it their natural hair color may make them look ashy.

To prevent a harsh look, Christo uses a technique called Smart Lights, where he takes individual strands of highlights and lowlights. He says it creates a natural look without a demarcation of color.

“The curl looks more defined and has more shine,” he says. “The overall look is warmer.”

Massey uses a technique called “pintura,” where she paints the hair curl by curl with warmer shades like toffee and auburn. Often she might use four or five different colors to achieve a natural look.

“If it’s all one color, it’s a block not a shape,” she says. “By highlighting them, we’re individualizing the curls.”

And the color will need to be re-evaluated on a regular basis.

“Often, what worked 10 years ago isn’t working for them anymore,” Cutler says. “It may be that they’re getting more gray. That’s something people don’t think about because they never allow their natural hair to come in to see whether they’re now 70 percent gray rather than 20 percent gray.”

Christo’s client Anne is in her mid 40s. He keep her curls long, and color plays a big role for her style. The hair is cut in irregular layers to avoid a pyramid look and is contoured according to her face structure so it can give her a lift. A one-length haircut would not work for her because it would pull down her face, aging her. Her color is a combination of earthy tones and sun-kissed highlights that sparkles her face. ‘I call it Chromavision,’ says Christo. ‘The key for being able to wear long hair and still look good is the right combination of cut and color. It is best to always consult with your hair designer and the color director of the salon prior to your appointment.’