The best carrots will be plump and have a vibrant orange color. Their surface should be smooth and free of any cracks. Try to avoid carrots that have strings dangling from their bottoms (but if these are your only option you could cut them off). If you can, look for carrots that are in bunches (that still have the leaves at the top). You can use the leaf color to determine the age of the carrots–a faded green or yellow means they might be too old. Carrots will last several weeks in the fridge but will start to lose flavor and nutritional value, so try to use or eat them within a week of buying.