Some women change their hair color like their underwear. Okay, maybe not that frequently, but many of us struggle to find one color and stick with it. Unfortunately, all of that trial and error can result in a permanent bad hair day. At-home hair coloring isn't something that should be taken lightly. There are certain things you should always keep in mind. Before getting started, you have a big choice to make and of course, that's the color. A good rule of thumb is to never go two shades darker or lighter than your current color. One expert points out that out-of-the-box colors don't afford you the luxury of tweaking how much peroxide is in the mix. So it's better to be safe than sorry. If you aren't sure you're going to be happy with the end result, give yourself an out by opting for a semi-permanent hair color. Although your color options are more limited, it fades with each wash. If you've never colored your hair before and you're determined not to visit the salon, recruit an experienced friend to lend a helping hand the first couple of times. Veterans will steer you clear of the hair-raising mistakes that can turn your hair into a hot mess.