Learning to use the potty is a milestone in your child's life. You probably can't wait to put the changing table in storage and toss away the diapers. But toilet-teaching can be an extremely frustrating phase, so be patient. Most children are able to master the potty between the ages of 2 and 3. As any parent who has gone through the process will tell you, it can take weeks -- or months. The most important strategy, experts say, is to let your child decide when she's ready. Studies have shown that many kids who start before 18 months won't be fully taught until age 4, while children who start around age 2 tend to be successful by age 3. Daytime control usually comes first; it may take longer for your child to stay dry through the night.