A playpen or play yard help both parent and baby. Parents feel better knowing their baby has a secure, interesting place to play. The baby develops his or her physical and mental abilities by exploring all the features of the playpen and the toys provided.
Safety is the first consideration, of course. Babies vary naturally in how vigorous they are. Some are quieter, others bounce all over the place at a very early age. A good playpen should stand up to the hardest punishment the baby can deliver, over the months or years they will use it.