These signs may be as simple as your child telling you when he has dirtied his diaper, your child staying dry all night, your child asking questions about using the potty, and your child's aversion to her soiled diaper.
For other occasions, remember that you can reuse the diaper cover with a new liner unless the cover has also been dirtied.
A dirtied leather tricorn hat over felt laced with gold trim, and a long pirate trench over a waist coat.