This is really up to you. Most play fences are good for ages 3-24 months, but you can use them longer depending on your child. The only concern with using them past that age is that your child might figure out how to get out. Climbing could be a danger, as well as tipping over as your child gets stronger. Other than that, you can use the fence for as long as you feel you need that safe space to keep your child contained.