Playpens are usually used when babies are 4 months old. This is because during this period, the baby's salivary glands begin to mature, resulting in increased drooling. Bibs can help absorb saliva. However, most babies start learning to crawl when they are 5 to 7 months old. At this time, parents usually buy crawling mats and playpens to protect the baby from injury while crawling. Bed guardrails can be used from when your baby is five or six months old to over two years old. Some babies can turn over or even crawl when they are three months old, so some parents will start using bed rails when their babies are five months old.

Based on the above information, the baby playpen can be used from the time the baby is four or five months old until the baby is about two years old. However, the specific usage time needs to be determined based on the actual development of the baby and the family environment.

Nowadays, more and more baby products are appearing in people's sight, which allows parents to leave their babies alone with peace of mind. Crawling mats and playpens are common baby products. One is to allow the baby to crawl on the mat and avoid injury. The other is to surround the baby within a certain area to prevent the baby from crawling to other places and causing danger.

If you want to buy a crawling mat fence for your baby, you should usually buy it before the baby learns to crawl, because these fences are usually made of plastic. After buying them first, put them in an open place for a period of time to remove some bad smells. And it must be disinfected before use. Sometimes babies will touch the fence directly with their mouths to prevent bacteria from entering.