Play in the yard
When kids are ready: 2 and up
Look for these signs: Your toddler is able to leave your side for short periods of time and is curious about exploring.
How to start: Supervise your 2- and 3-year-old closely, even if your lawn is fenced in -- there's no way to predict when she'll figure out how to unlatch a gate door, or scale a wall, or pick your thorny roses.
Once your child's 4 or 5, she's ready to play on the sidewalk or in the yard in front of your house. But watch her closely and teach her not to wander off. "Draw a large box on the sidewalk with chalk and tell her to stay inside the lines while she plays," says Marguerite Kelly, author of "The Family Almanac" advice column. Keep an eye out from your steps.
By the time she's 8, she'll probably want to hang around with neighborhood friends. Be sure she knows how far down the street she can go, that she can't pop into anyone's house without your permission, and that she's got to check in regularly.
At least one parent should keep tabs on the posse. "Several children on our street between the ages of seven and twelve play together outside, and I watch them from the kitchen window while I make dinner," says Leslie Callahan of South Bend, Indiana, the mother of two boys, ages 11 and 7.
Alix Finkelstein, a mom of two in Brooklyn, frequently writes about parenting issues.