Baby bedding should be pleasing to the eye as well as functional; A simple plastic covering placed over the mattress will save many hours of unnecessary cleanup time and still be hidden from sight under the colorful sheets.
Obviously, any bedding that you buy should be capable of being washed, and make sure that you have several different sets, because at some point you will find yourself with all of the others dirty and in need of a clean one! Your pediatrician is the most reliable source of information about what sheet sets are appropriate for your baby at each stage of his or her development. Even though the doctor may advise you not to use fluffy blankets for you little ones at night you will still have plenty of chances to use that one-of-kind heirloom blanket or quilt from Grandma during the day.