The day your baby rolls over for the first time, takes his first steps or utters his first words is a big day indeed, both for you and your little one. If your child learns these skills, known as developmental milestones, more or less on schedule, it’s a sign he’s developing properly.

But if he doesn’t, what does that mean — and when is it time to panic, or at least call the pediatrician?

Missing a milestone could be a first clue to a condition such as autism or a metabolic problem. Or it could mean nothing at all.

“I like to remind parents that milestones are just points along a path, not the be-all and end-all,” says Mark Gettelman, MD, FAAP, founder of Doctor Goofy GettWell Pediatrics, a mobile and telemedicine pediatric practice in Phoenix. “It’s just like if a friend were driving from New York to Los Angeles. You might plot points for him to stop along the way, but if he were late getting to one, or skipped one altogether, that might not mean disaster.”

Here’s a look at some major developmental milestones and what to do if your child doesn’t hit them on time.

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Rolling over

Average age when it happens: 2 to 4 months

Why it’s important: “It shows she has the muscle strength and ability to coordinate that act,” explains Gettelman. “By four months, you usually see kids roll at least from front to back.” But if yours doesn’t, he adds, it doesn’t always mean something is wrong. “Sometimes a child just hasn’t been put on his tummy enough, especially since we recommend putting babies to sleep on their back. It could also be a personality thing. Some kids are desperate to see what’s on the other side; others are laid back and cool.”

Still, bring it up to your doctor if the four-month mark passes without a flip, just to rule out possible muscle or motor control problems.

Head control

Average age when it happens: Around 3 months

Why it’s important: If your child can lift and turn her head, she’s again showing strong muscles and good coordination. Unlike some other so-called milestones, this one really fits the bill: “Almost all babies show head control by the time they’re three months old,” Gettelman notes. If your little one doesn’t, alert your pediatrician. The child could have a metabolic or muscular issue that needs to be addressed.

Smiling and tracking objects with the eyes

Average age when they happen: Around 3 months

Why they’re important: Both acts are evidence of coordination and social development. “If you’re not seeing these behaviors on schedule, it could mean that your baby has a visual problem, so speak with your pediatrician,” says Gettelman. It may simply be a visual-development delay that will resolve on its own.

A lack of gummy grins also isn’t cause for insta-freaking. Sometimes parents think their baby is poker faced, but they may simply be missing a subtle smile. “It could also be your child’s personality,” Gettleman adds. “Some kids just aren’t big smilers and laughers.”

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Sitting up

Average age when it happens: Around 6 to 8 months

Why it’s important: Plenty of muscle control and gross motor skill goes into this maneuver. It’s a good sign that both these abilities are developing nicely, as is trunk strength. But don’t get upset if it doesn’t happen on time, or if your child seems content to lie on his back or tummy. “Sitting up can be based on a lot of training, and how often you’re giving him a chance to practice,” says Gettelman. If your baby doesn’t sit up by 8 months, mention it at your well-child checkup; most likely your pediatrician will tell you not to worry if your child seems to be developing normally otherwise.

Speaking

Average age when it happens: At around 12 months

Why it’s important: Naturally, it shows good muscle, social and cognitive development. “But I will see a good percentage of children who don’t speak at the one-year mark,” says Gettelman. Mention it to your doctor, but if your child is hitting most other milestones, you’ll probably be told to give it time.

To help your child along, talk to him often, “and use real words, not baby words, so he learns the proper names of things,” says Gettelman. Read books to your little one, too. If he still hasn’t said a word by 15 months, your pediatrician might want to examine him again for issues such as a hearing impairment.

Pretending and imitating

Average age when it happens: Around 18 months

Why it’s important: “It shows good cognitive and imaginative growth, as well as the ability to perceive different personalities and understand things outside yourself,” Dr. Gettelman says. While it’s a definite plus to see games of make-believe at the year-and-a-half-mark, a lack of them isn’t necessarily a cause for alarm. Your doctor may ask other questions about your child’s overall development to get a sense if it’s on track.

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Looking at objects you point to

Average age when it happens: 15 to 18 months

Why it’s important: Believe it or not, there’s a big social component involved. “It shows your child is interested and engaged and is able to put himself in your shoes,” says Gettelman. Children who have autism may not have these abilities. So do tell your doctor if your baby seems to ignore you when you point at things. Rest assured, though, it doesn’t necessarily mean anything serious. “It could be that he is distracted, or you’re in a new place and he’s a little intimidated,” Gettelman explains. “He could just not want to look!”

Following commands

Average age when it happens: 18 to 24 months

Why it’s important: “Go get your shoe” asks a lot of your baby. It’s a request to form a mental image and keep it in mind long enough to act on it. If your child succeeds, it’s a great sign that his vocabulary, memory, cognitive processing and muscle skills are all online. If your child has failed to carry out a single request you’ve made by his second birthday, talk to his doctor. He may want to examine him closely, but keep your cool: You could just have a stubborn 2-year-old!

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