Step 7: Adding snaps and buttons
Space your snaps evenly down the front of the sweater making sure to put one at the top and bottom and the rest evenly spread out along the length. The number of buttons you add is your choice, or follow the suggestion given in your knitting pattern.
Sew the snaps inside the sweater and then sew the buttons on the top of the front placket just above the snaps inside. The buttons are purely decorative.
That's it! You've made a warm, cosy sweater for baby and made the mom's job much easier too.
Although I haven't tried it, I don't see why the same method couldn't be used for an adult sweater if you wanted to add warmth. Adults, however, don't usually find buttoning a sweater too difficult.