Coloring your own hair, whether you’re a man or a woman, can save money ($50 to $150 or more each time). It also can save time and give you great-looking hair—if you do it right. Although modern home hair-coloring kits make it easier than ever to get natural-looking results, mistakes can damage hair and lead to a do-it-yourself look. Avoid these common errors…

    • Mistake: Going too dark or light.

Too light: A color that is much lighter than your natural shade can wind up looking brassy. Reason: Brown hair has underlying red and orange pigments. The chemicals in light-colored dye bring out those red-orange tones.

Too dark: If you go dramatically darker and then change your mind or don’t like the effect, the dark color is difficult to correct. Putting a lighter shade over darker dye can damage your hair but won’t lighten the color—although it might leave hair darker at the ends than the roots, a telltale sign of a home job.

Better: Choose a shade that matches your current color or that is just one or two shades darker or lighter. If you are lightening your hair, use a cool or ash tone to control brassiness. If you are going darker, consider starting with a semipermanent tint. Because the tint fades gradually over time, you won’t have to use harsh chemicals to strip out the color if you don’t like it.

    • Mistake: Picking the wrong color for your skin tone. The hair color you love on a friend or celebrity may not flatter you. If your skin has yellow or olive undertones, shades that are cool—such as platinum blond or jet black—will make you look sallow. If your skin has pink undertones, warm hair color can make your skin look reddish or blotchy.

To determine your skin tone: Turn your hand so that the palm faces up, and look at the veins on your wrist. If your veins look greenish—and you look best in peach, orange, gold and tan clothing—you have warm undertones. Choose a warm hair color such as honey, bronze, caramel, amber or gold.

If your veins are blue or purple—and you look better in bluish reds and purples than in yellow or orange—you have pink undertones. Opt for a cooler shade such as ash, smoke or champagne.

    • Mistake: Not adjusting for gray. As hair becomes gray, hair texture and skin tone also change. A dark color that used to flatter you may now look harsh against your skin. Also, gray hair does not absorb color as easily. It may pick up more of a dye’s underlying blue or pink tones, resulting in a muddy color.

Better: Use a product specifically designed to cover gray. Your hair will absorb the color better, and the undertones will be balanced to look natural.

If you have been dying your hair dark, try lighter shades as you gray.

  • Mistake: Coloring too often—this makes hair dry and lifeless.Better: Color the whole head no more than every six to eight weeks. When roots begin to show after four weeks, either use a root touch-up product or use your usual product and follow the instructions for touching up new growth.