Hair color is a tricky business. Knowing what shades work well with which skin colors, how to place highlights for maximum impact or how to get color that lasts are all topics that send shudders down the spines of mere mortals who're equipped with nothing but a celeb photo they want to copy and a box of hair dye they're praying will work wonders. But, with an estimated 50 percent of women 25 and older coloring their hair (and dropping a whopping $2 billion in dye and bleach each year), it's abundantly evident that this is not a passing trend.

Happily, there are color gurus who can point us in the right direction and get us off on the right food. One such authority is Brad Johns, the Color Director for Red Door Spas. Johns, who has honed his skill at some of the top salons in the world, including Jean Louis David, Oribe and Bruno Dessange, believes foremost that hair color should harmonize with (and set off) eye color and also thinks that skin tone and time of year should be taken into consideration.

Here, the color expert himself addresses five of our readers' pressing hair color concerns:

Question: "Every time I color my hair, the roots start to fade within a week.I use shampoo and conditioner for color treated hair.Why does this happen and what can I do to get the color to stay on my roots?" -- Jennifer L.

Answer: "You're using the wrong color when doing the roots," says Johns."Hair color should last 3-6 weeks or until the roots start to grow out. The ashier the color, the less gray coverage. The warmer the color, the better for covering grays," he counsels. Also, be sure that you're using a permanent color that's intended for covering gray because semi-permanent color definitely won't last. And, Johns says to definitely wash and condition using products intended for color-treated hair. "I love the Davines shampoos and conditioners for protecting color. They're my favorites," he says.

Question: "My hair is dark and I want to dye it red. What's the best way to do this and maintain the shade?" -- Norma

Answer: "The best way to get the right hair color is to go to a professional. If you pick the wrong red shade you (or we) may not be able to get it out or fix it," Johns warns. And, when it comes to choosing the hue, he offers this sage advice. "When you go red, it should be a red that appears in nature, not a red that appears on a clown or a vegetable. Look for coppery, cinnamon, strawberry and auburn reds. Avoid aubergine, cherry, orange and pumpkin hues. If it doesn't appear in nature, it won't appear natural on you."

Question: "Can color-treated hair be highlighted or streaked?"-- Jennifer D.W.

Answer: "For most of the clients I do, I color them first, then I highlight them," Johns says. And there's a reason to proceed in that order."Color-treated hair should be highlighted and streaked so it looks more natural, [otherwise, the color is too uniform]," he says.

Question: "Is there anything less damaging than permanent color to cover up grays?" -- Melody

Answer: "Permanent hair color is not damaging -- unless you use it the wrong way [following the directions on the box -- to a tee, is essential]. If it is done right, permanent hair color doesn't damage hair and it's the best way to cover gray, that's what it's made for," says Johns. If you're concerned about dying too often or don't like the way the color makes your hair feels, simply touch up your roots when needed. There's no reason you have to bring the color through your entire head of hair each time.

Question: "How can you extend the life of hair color while combating dandruff?I haven't found an anti-dandruff shampoo that doesn't cause my hair to fade." -- Jessica

Answer: This is a conundrum that dandruff sufferers face. "All anti-dandruff shampoos cause color fading because they are like a medicine for your scalp," says Johns. "they cure the dandruff, but do cause the color to fade and, the only way to extend the life of any hair color is to use the right shampoo and conditioner." But, don't despair, there may be other ways to combat your flakes. Johns recommends, "asking your doctor how long you need to use the product, and see if there is any other way to treat your dandruff."