While it may be tempting to arrive at your color appointment wearing a topknot, it's best to show up with your hair as you normally wear it. That way, your colorist has a better idea of how to place your color. "If someone is going to wear their hair curly, you want to make the color a bit more dramatic, whereas if someone is going to wear it straight, you want it to look more subtle," says Hazan. "[The goal is] to get it to look good on both curly and straight hair."Lighting is another important factor to consider when choosing color. This is particularly important for someone like Beyoncé who is often on stage. "If the lighting is warm, you want to use something that's [cooler], because you have to balance out what the stage looks like and how that's going to read to people," says Hazan. "Hair isn't going to look amazing in every single lighting, but it has to look good in 90% of lighting."Bleaching and dyeing your hair put a lot of stress on your locks. That's why Hazan created her line of products with ladies like Beyoncé, Madonna, and J.Lo in mind. "All these women blowdry, flat-iron, and curl [their hair] every single day, and color is the number one thing they can't live without," says Hazan. Her products (which include shampoo, conditioner, hair gloss, treatments, and touch-up sprays) are formulated without sulfates, sodium chloride, or parabens, meaning they're gentle enough to use on fragile, color-treated tresses.According to Hazan, if you have color-treated hair, you can get away with washing your hair every three or four days, but Hazan warns against skipping too many days between washing. "I'm a believer in a clean scalp," she says. "I'm not a big fan of dry shampoo, because I feel like that clogs your pores." Your scalp is an extension of your skin, she explains. And like the skin on your face, your scalp should be cleansed and treated with care.