When Bobby Berk first started working as an interior home designer, the teenage children of his clients would stay in the background, deferring to the choices of their parents when it came to their rooms. "But now, the teen has become the client," says Berk, a regular on HGTV and the founder of his own homeware line. "I make a separate presentation to them. Their input has become way more important - even if the parents are still paying the bill." Designing a teenager's room presents its own challenges: a person evolves tremendously between the ages of 13 and 18, their interests fade in and out and their personalities are still forming. To that end, designers are forced to have a long-term view when creating teen bedrooms, aware that it may become a guest suite or television room when they go to college. And given that young people today are so technology-minded, designers have to keep in mind how to incorporate their nerdy needs alongside a quiet study and sleeping space. "So many kids have gaming systems, computers, iPads and iPhones around which they socialise," said Berk, who plans to open his first store in Hong Kong in the next year. "We have to always make sure they have their own space, with great seating, a place they can have their friends over to hang out instead of going out and getting into trouble." Interior decorator Kristen Nugent, founder of an eponymous studio in Los Angeles, is putting the final touches on a 45,000 sqft mansion in Newport Beach owned by a family with four children, two of them teens. What she was most impressed by was how the children had already cultivated their own styles. The 15-year-old girl requested a clean, simple white space in which the focus would be on her biggest interest - polar bears. The 14-year-old boy is a huge sports fanatic, so one wall was devoted to a collage of pictures of his basketball idols. "We had full-sized murals of his favourite sports fans and ways to display his own awards and trophies," says Nugent. Designers say they and their teen clients love the flexibility of wall decals. Detroit, Michigan-based company Fathead makes wall accents using life-size images of iconic athletes. Wake up to an image of US soccer star Clint Dempsey dribbling a ball or Tim Howard diving to save another goal. Astronomy buffs can paste on six-foot-by-four-foot images of the solar system, while science fans can have a simplified diagram of the digestive system. Designs can be customised as well. Name Bubbles, a New York-based company that started off making labels for children's lunch bags and clothes, recently expanded into wall decals. Wall Monkeys, also based in the US and boasting one of the largest inventories of images in the world, makes decals featuring skulls and silhouettes inspired by martial arts, which are popular with teenagers. Before redecorating, however, designers advocate taking the time to understand the teenage mindset. "It is important to make sure the child has space for their personality to develop," said New York-based designer Cecilia Dupire. "The room should also be thought of as a place where the teen can develop their creativity." In some of her projects, she has incorporated elements like mirrors or walls that can be used as canvases, involving a surface that can be wiped clean or large metallic boards on which to hang artistic creations. Decorators advocate prolonging the aesthetic appeal of the room by sticking to a neutral palette for the main furniture items and adding pieces that reflect the teen's needs and interests. "I like to have a five to 10-year plan," said Nugent. "There should be a dedicated space for whatever the current interest is. You want the teen to feel like this is their own space, and they are not forgotten in the process." Brands like Fatboy (available in Hong Kong through Everything Under the Sun, in Horizon Plaza) are popular among decorators working on teen spaces: the groovy beanbags are age-appropriate and modern. As teens grow, the beanbags can be moved to another room, replaced with a great lounge chair or a small sofa. Berk also suggests looking for worthwhile extras, like desk lamps and night table lamps that feature USB ports - something an increasing number of lighting designers are thinking about - and removable wallpaper. Essentially, he says, the more flexible a teen's space is, the less fixated on a particular theme, the better. "Previously, adolescents would like themes - a favourite comic-book character or movie star. But they have more modern tastes now. They don't want to be defined by something that specific anymore."