Every baby is different.

I say this all the time.

Different temperaments. Different feeding patterns. Different sleep needs. Different sensory preferences. Different developmental trajectories. Different families.

But somewhere along the way, “every baby is different” seems to have evolved into the idea that using averages, age-related norms or population data when working with babies is somehow inappropriate.

I disagree.

Your baby absolutely is an individual.

But when I don't know your baby yet, starting with what is typical for babies their age is often the most sensible, evidence-informed and efficient place to begin.

And this isn't something unique to baby sleep.

It's how healthcare and developmental science work every single day.

 

We Use Population Data for Babies All the Time

Imagine taking your six-month-old to see your doctor or Well Child provider.

They weigh your baby.

Do they say:

"Well, every baby is different, so population data are irrelevant. Let's just see what happens over the next year."

Of course not.

They plot your baby's measurements on a growth chart.

Growth charts are built using population data. Your baby's weight, length and head circumference can be compared with reference data for other children of the same age and sex.

Does being on the 25th percentile mean something is wrong?

No.

Does being on the 75th percentile mean your baby is healthier than the baby on the 25th?

No.

And does your baby need to sit precisely on the 50th percentile because that's around the middle of the population?

Absolutely not.

The reference data give us context.

Then we look at the individual baby.

Their previous growth.

Their trajectory.

Their feeding.

Their health.

Their development.

Their genetics.

That's individualised care built on population evidence.

And that's an important distinction.

 

“Average” Doesn't Mean “Everyone Should Be This”

I think this is where a lot of the resistance to averages comes from.

People hear the word average and interpret it as:

“Your baby should do exactly this.”

That's not what it means.

An average tells us something about what is typical within a population.

It gives us a reference point.

Some babies will fall above it.

Some will fall below it.

Some will be significantly different from it.

That's exactly why the average is useful.

Without knowing what's typical, it's much harder to recognise what isn't.

Think About Developmental Milestones

We do exactly the same thing with development.

We know approximately when babies typically begin to:

Roll.

Sit.

Crawl.

Babble.

Pull themselves to stand.

Walk.

We don't expect every baby to achieve those milestones on exactly the same day.

There is a range of normal development.

But imagine saying:

"Every baby is an individual, therefore knowing when babies typically walk is meaningless."

That would make no sense.

Developmental norms help parents and health professionals understand what is broadly expected and, importantly, identify when something might warrant closer attention.

Individual variation doesn't make population data useless.

Population data help us understand individual variation.

Medicine Is Full of Reference Values

Take heart rate.

A newborn has a different expected heart-rate range from an older child or an adult.

Respiratory rate changes with age too.

So does blood pressure.

Blood-test results are interpreted against established reference intervals.

Paediatric medication doses are commonly calculated using factors such as a child's weight, age or body surface area, depending on the medication.

Healthcare professionals don't throw away those reference values because “every child is different.”

They start with what we know about the population and then apply clinical judgement to the individual in front of them.

This is a completely ordinary part of evidence-informed practice.

 

And We Already Do This With Sleep

Here's where things become particularly interesting.

We already accept age-related population recommendations when we're talking about how much sleep babies need.

The American Academy of Sleep Medicine recommends that infants aged 4–12 months regularly obtain around 12–16 hours of sleep per 24 hours, including naps.

That doesn't mean every six-month-old needs exactly 14 hours.

One baby might thrive on less.

Another may genuinely require more.

But the research gives us a sensible range within which to start thinking.

And once we know approximately how much babies of a particular age tend to sleep, we also know something else:

Approximately how much time they spend awake.

So Why Would We Pretend We Know Nothing About Awake Time?

Let's take a hypothetical six-month-old.

Suppose that baby sleeps approximately 14 hours in 24 hours.

That leaves approximately:

10 hours awake.

Now suppose that baby takes three naps.

Those three naps divide their day into roughly four periods of wakefulness:

Wake → Nap 1

Nap 1 → Nap 2

Nap 2 → Nap 3

Nap 3 → Bedtime

Ten hours of wakefulness divided across four waking periods gives us an average of approximately:

2.5 hours awake at a time.

Does that prove this particular baby's ideal wake window is exactly two hours and thirty minutes?

No.

And I would never claim that it does.

Maybe they comfortably manage three hours before bed.

Maybe their first wake period is shorter.

Maybe they're a higher-sleep-needs baby.

Maybe they're a lower-sleep-needs baby.

Maybe their naps are distributed differently.

But approximately 2–3 hours gives me a pretty sensible place to start looking.

Because Here's the Alternative...

Imagine I refused to use any age-related sleep information because your baby is an individual.

I could start with:

10 minutes awake.

Didn't work?

Okay.

Tomorrow let's try 15 minutes.

Then 20.

Then 25.

Then 30.

We'll just keep increasing the wake period in tiny increments until eventually we discover your baby's individual “sweet spot.”

Would that be more individualised?

Technically, perhaps.

Would it be sensible?

Of course not.

I'd be deliberately ignoring useful information we already have.

If everything else about this six-month-old suggests that somewhere around 2–3 hours is likely to be reasonable, why would I begin at 10 minutes?

And equally, why would I start at six hours?

We already have information that helps us narrow the search.

Using it makes the process more efficient.

Starting With Average Helps Me Find Your Baby's Individual Faster

This is the part I think gets missed in discussions about individualised sleep support.

Starting with population averages isn't the opposite of individualisation.

It can actually help us individualise more quickly.

If I know roughly what is typical for a six-month-old and your baby is doing something very different, that's useful information.

Perhaps your baby consistently needs substantially less awake time.

Why?

Perhaps they're particularly high sleep needs.

Perhaps their overnight sleep is fragmented.

Perhaps they're unwell.

Perhaps they've accumulated sleep debt.

Perhaps their naps are very short.

Or perhaps that genuinely is simply their normal.

Likewise, if your baby consistently needs significantly longer periods awake than we'd normally expect before they're ready to sleep, I want to know that too.

Maybe they're lower sleep needs.

Maybe we're offering too much daytime sleep.

Maybe bedtime is too early.

Maybe we're trying to achieve more sleep than this individual baby requires.

The difference from the expected pattern gives us information.

But I need a reference point before I can identify that difference.

This Is Why Good Sleep Consultants Don't Just Hand You a Chart

A wake-window chart should never replace assessment.

I don't want a sleep consultant looking at a baby and saying:

"You're six months old. The chart says 2 hours 30 minutes. End of discussion."

That's not individualised care.

But I also don't think good practice means throwing away everything we know about infant sleep development and starting from zero with every baby.

The skill is knowing:

What would I broadly expect at this age?

Then:

What is THIS baby showing me?

And finally:

What do I need to change?

That's where professional judgement comes in.

Sometimes Being Outside the Average Is the Clue

This applies to far more than wake windows.

Imagine I'm working with a six-month-old who is taking six naps every day.

I'm not going to say:

"Every baby is different, so that's completely meaningless."

I'm going to ask why.

How long are those naps?

How much total sleep is the baby getting?

How long can they comfortably remain awake?

Are they waking after very short sleep cycles?

Is something continually interrupting their sleep?

What's happening overnight?

Likewise, if a six-month-old is taking one nap and staying awake for seven hours at a time, I'm interested.

It doesn't automatically mean something is wrong.

But it's significantly different from what we'd generally expect developmentally.

That difference tells me where to investigate.

This is exactly why knowing typical patterns is valuable.

Averages Aren't Rules. They're Shortcuts.

Perhaps that's the simplest way of explaining it.

An average is not an instruction.

It's information.

It helps us say:

"Based on thousands of other babies at approximately this developmental stage, somewhere around here is probably a sensible place to begin."

Then we assess.

We observe.

We adjust.

Maybe we move earlier.

Maybe we move later.

Maybe this baby sits beautifully around the expected range.

Maybe they're an outlier.

That's fine.

The goal was never to make the baby fit the average.

The goal was to use the average to find the individual baby's needs more efficiently.

Evidence-Based and Individualised Aren't Opposites

There seems to be an emerging idea in parts of the infant sleep world that being “responsive” or “individualised” means rejecting schedules, averages, norms and age-related expectations.

I don't think those concepts are incompatible at all.

I can know what research tells me about typical infant sleep AND watch the baby in front of me.

I can understand sleep averages AND respond to temperament.

I can consider age-appropriate wakefulness AND pay attention to sleep cues.

I can use developmental norms AND recognise that this particular baby doesn't fit neatly within them.

In fact, that's exactly what individualised evidence-informed practice should look like.

We don't need to choose between science and responsiveness.

We use the science to inform where we begin.

Then we use observation and professional judgement to decide where we go next.

So Yes, I'm Going to Assume Your Baby Is Fairly Average — At First

And I don't mean that dismissively.

I mean that statistically.

Before I know anything else about your baby, the most reasonable starting assumption is that they're probably somewhere within the broad range of what's developmentally typical.

That's far more rational than assuming they're an extreme outlier before I've seen any evidence that they are.

Then your baby gets to prove me wrong.

And if they do?

Great.

That's information.

We adjust.

Because the objective isn't to make your baby conform to an average.

The objective is to get to your baby's individual needs as quickly as possible.

Population data help us narrow the search.

Observation helps us refine it.

And your baby's response tells us whether we've got it right.

So yes, your baby is unique.

Yes, your baby is an individual.

And yes, when I'm first deciding where to start, I'm probably going to assume they're reasonably average.

Not because I don't see your baby as an individual.

Because starting with what we already know is usually the fastest way to discover exactly how your baby is different.

Why Do Sleep Averages Feel So Much More Personal?

There's another reason I think parents are particularly uncomfortable with averages when we're talking about sleep: sleep is emotional.

If your baby's resting heart rate sits somewhere different from the population average but is still healthy, you probably don't feel as though you've failed your baby. If your baby doesn't roll at exactly six months, you don't usually spend 45 minutes that evening listening to them cry while wondering whether you made the wrong decision. We understand instinctively that developmental milestones vary, and there isn't necessarily an immediate emotional consequence when our baby sits slightly outside an average.

Sleep can feel very different.

When we get the timing wrong, a baby might resist the nap. They might cry. They might become overtired or frustrated. A parent may spend 30 minutes trying unsuccessfully to settle them, only for the baby to wake again shortly afterwards. And crying is designed to trigger a powerful emotional response in a parent.

Suddenly this isn't an abstract discussion about population averages.

It's your baby crying in your arms.

And when that happens, parents understandably want to know why.

Was I supposed to put them down earlier?

Did I keep them awake too long?

Have I made them overtired?

Am I doing something wrong?

Have I harmed their attachment?

Why did the sleep consultant tell me to do this?

When parents are exhausted and their baby is upset, it's very easy for an imperfect starting recommendation to feel like evidence that the entire approach was wrong—or that the professional giving the recommendation didn't understand their baby.

But an initial recommendation needing adjustment doesn't mean the starting point was unreasonable.

If I suggest an age-appropriate wake period based on what we know about babies at that developmental stage and your baby consistently shows me they need 20 minutes less, that's not a failure.

That's the assessment working.

We started with the best information available. Your baby gave us additional information. Now we individualise.

The same would be true in many other areas of child development. Your baby's measurements, developmental trajectory or physiological values may sit somewhere different from the population average, and healthcare professionals interpret that information in context.

The difference is that those variations don't usually involve an exhausted parent standing beside a cot listening to their baby cry.

Sleep comes with immediate emotional feedback.

And that can make us expect a level of precision from sleep recommendations that we don't expect from many other developmental averages.

A wake window is not a promise that your baby will fall asleep peacefully at exactly that time.

It's a hypothesis based on what we know about babies of a similar age.

Then we test it against the most important piece of information we have:

the baby in front of us.

And if that baby tells us something different?

We adjust.

That's not ignoring their individuality.

That's how we discover it.

 

Emma Purdue

Emma is the owner and founder of Baby Sleep Consultant, she is a certified infant and child sleep consultant, Happiest Baby on the block educator, has a Bachelor of Science, and Diploma in Education. Emma is a mother to 3 children, and loves writing when she isn't working with tired clients and cheering on her team helping thousands of mums just like you.