For many parents, it starts with a child’s nagging plea: “Why can’t you let me cross the street by myself?” or “When are you going to let me walk home from school on my own?

It would be so nice if that line of questioning stopped there.

But since parenting is all about “letting go,” prepare for a continuing onslaught of those kinds of questions – up through the teen years: “Can I go to the mall with my friends?” “Can I get a tattoo?” “Joey and I want to go out on a date alone.”

Grappling with when to let kids take on the world without direct adult supervision has always been a challenge for parents. But the question is more significant today, when the world is rapidly changing and much less secure. You want your child to have the independence you had while growing up, but you also want to protect him from risks that just weren’t there during your own childhood.

“Children vary tremendously,” says David Elkind, Ph.D., a renowned child-development expert and author of the landmark book The Hurried Child. “One may be ready to do certain things; another may not be. Parents need to rely on their good common sense.”

That means knowing intuitively whether your child is ready to be safely on her own. “You wouldn’t leave an infant alone, for example,” says Elkind. “And it can be dangerous to let a young child cross the street alone. It takes time and energy to make sure a child really is cautious.”

As parents start to hear those “when can I … ?” questions, teaching them what to expect and how to react in different situations goes a long way toward having confidence about their safety in the world. Here are some basic, age-appropriate guidelines for preparing kids to be more independent, so that you can feel more secure when they do strike out on their own:

Ages 5 to 9

Young children need to be taught how to accomplish a variety of independent activities safely – crossing the street, riding a bicycle, answering the phone at home, etc. Parenting and safety experts recommend teaching a child how to do something safely on his own and then monitoring his first attempts.

“If you live in a safe cul de sac and your child can cross the street over to a friend’s house while you watch out the window, then a 5- to 6-year-old child can cross the street,” says Jan Faull, M.Ed., a noted parenting educator, author and lecturer. “In more urban areas, though, where there’s lots of traffic, it’s probably not a good idea to allow a child to do that until they’re at least 10.”

Faull herself monitored her third child when he wanted to go to a neighborhood park on his own to play with friends. Initially, she would follow her son to the park at a distance, to make sure he got there safely. Then she would drive by the park a few times to check on him while he was there. “I told him he could go to the park for one hour with at least two friends. We identified two houses near the park where he could go if anything unforeseen occurred.”

At what age can parents start to let a child walk the neighborhood or play in the park unaccompanied by an adult? Faull believes that, generally, kids under age 10 aren’t quite ready to judge the trustworthiness or intentions of an adult who might approach them. “Children age 10 and over can consider many factors; they can see that someone’s intentions are not just on the surface, that there’s a hidden agenda,” she says. “So that’s about the age that I would look for.”

Ages 10 to 14

Budding adolescents, tweens as they’re often called, are asking for more independence at younger ages these days – from wanting to hang with friends at the mall or stay home alone to wanting to be in co-ed situations without parental supervision.

Again, child-development experts say it comes down to the individual child’s readiness and, of course, teaching the child about the safety issues involved. “I always go back to the fundamentals of child development,” says David Elkind, Ph.D., a renowned child-development expert and author of The Hurried Child. “Brain research confirms that young adolescents, ages 12 to 14, are not good at decision-making. They respond more emotionally. Understanding that, you want to be a little more thoughtful about what to allow them to do.”

Kenneth Ginsburg, M.D, co-author of “But I’m Almost 13!”An Action Plan for Raising a Responsible Adolescent, also points out the differences in emotional maturity between boys and girls at this age. “Generally, girls mature about two years faster than boys, on average. Girls really are more pre-teenagers when a lot of boys at this age are still very much little boys.”

When your tween asks for specific independence, Ginsburg says, “Ask yourself, ‘What is right for my child? Is he or she prepared? Have I put into place a safety net so that I really know he or she is capable of acting responsibly with the limits I have set?”

If you aren’t entirely comfortable with a situation, Ginsburg recommends telling your child this and coming up with rules that will make you both feel more comfortable.

If, for example, your seventh-grader wants to go to the mall with friends, let her know that you want her to stay with her group of friends and not strike off on her own, that you want her to check in with you by phone at regular times. Then, if something goes wrong, give the child an escape – a way that she can alert you to get her out of an uncomfortable situation while still saving face with her friends.

Ginsburg recommends that, starting at age 10, all families can have a code phrase: A tween can call home, tell his mother or father something like, “I’m going to be an hour later probably. Can you walk the dog?” The parent would then know that the child is in trouble or uncomfortable and can respond like a strict, unwavering caregiver. “No. Where are you?! I’m going to pick you up right now!”

“That’s what kids want,” Ginsburg says. “They want to do the right thing, but sometimes find themselves in situations they can’t negotiate. This is just the ‘blame me’ method. It provides them with an instant out, where they know they can call you anytime.”

14 and up

Teens are confronted with riskyactivities – sexual activity, drinking, drug use and more – all with the idea that they should be dealing with this on their own.

If parents have been lax with their kids from very early on, not setting or enforcing rules and limits, they’ll have a difficult time reining in their teens, warns Elkind. “It’s much easier to start tough and ease up than to start easy and get tough. Parents may start to get laissez-faire with young children and allow them to do a lot of stuff because they don’t want to get into an argument. But that backfires later on.”

Communication from early on is equally important, he says. “Start early with frank discussions, really listening to what your kids have to say and sharing with them your own perspective. Then in adolescence, you begin talking about some of these things (premarital sex, underage drinking, etc.). If you can establish good relationships and open communication early on, kids can understand that you’re not really trying to block their freedom, but are concerned for their well-being.”