To quote a popular children's book, "Everyone eats, so everyone poops." Until your child is able to use a toilet or potty and sleep through the night without accidents (even if you are practicing elimination communication), you'll need something to contain mess. You'll need diapers, a place to change baby, wipes (not necessarily disposable), a place to put the mess, and a bag for changing on the go. There are a lot of gadgets but chances are good you won't need them, and you won't know what suits you and baby until you learn about their and your needs.