There was a time when opening an advent calendar meant one thing: finding a tiny picture hidden behind a cardboard door.

No chocolate. No toys. No beauty products. No miniature bottles, jewellery, candles or collectables. Just a picture – and somehow, that was exciting enough.

Fast-forward to today and the humble advent calendar has become an entire Christmas category of its own. You can still buy the traditional cardboard versions, of course, but they're now joined by calendars filled with everything imaginable, reusable calendars designed to be filled at home and even advent candles that dispense with doors altogether.

So how did something so simple become such a huge part of modern Christmas?

And, perhaps more interestingly for retailers, why does the basic idea still work so well?

Before There Were Little Doors

The idea of counting down to Christmas is much older than the commercial advent calendar.

Families found all sorts of ways to mark the days leading up to Christmas. Religious images might be added to a wall, chalk marks could count down the days, and candles offered another simple way of measuring the journey towards Christmas.

The printed advent calendars we would recognise today began appearing in Germany in the early 20th century.

Their great innovation wasn't particularly complicated: turn waiting into an activity.

Instead of Christmas simply getting one day closer, every morning now had its own tiny event.

Open a door.

Reveal something.

Come back tomorrow.

More than a century later, that's still the basic formula behind almost every advent calendar on the market.

The Magic Was Never Really Behind the Door

Ask somebody about an advent calendar they had as a child and they may remember what was inside it.

But what they're more likely to remember is the ritual.

Getting up in the morning. Finding the right number. Opening the door. Realising somebody else in the family had opened theirs already. Accidentally opening number 17 when it was only the 12th...

The contents are almost secondary.

Advent calendars work because they divide one big wait into 24 little moments of anticipation.

Psychologists sometimes describe anticipation as part of the enjoyment of an experience itself. Christmas is particularly good at this: decorating the tree, Christmas music, lights appearing in windows, presents accumulating underneath the tree and, of course, counting down the days.

An advent calendar packages that anticipation into something physical.

Then Somebody Added Chocolate...

For generations of children, the next big development was considerably more important than anything happening in the world of printing.

Chocolate appeared behind the doors.

Suddenly the daily reveal wasn't simply something to look at. There was a reward.

And that seemingly small change points towards the reason the advent calendar has proved so adaptable.

The calendar itself isn't really the product.

The countdown is the product.

What sits behind each door can change completely while the idea remains instantly recognisable.

Once manufacturers understood that, the possibilities became almost endless.

From Chocolate to Toys, Charms and Collectables

Walk through a shop in November today and you'll find advent calendars for almost every imaginable interest.

Children's toy advent calendars have become particularly popular because they extend the experience beyond the few seconds it takes to eat a chocolate.

A miniature toy, charm, figure or collectable remains after the door has been opened.

Better still, 24 individual surprises can gradually become a collection.

A charm bracelet advent calendar, for example, isn't simply 24 unrelated gifts. Each day's surprise contributes towards something that develops throughout December. By Christmas Eve, the recipient has assembled something they can keep.

Toy advent calendars can work in much the same way, with children gradually discovering characters, accessories or small surprises throughout the month.

It's a very different product from the simple cardboard calendar our grandparents might remember.

Yet the mechanism that makes it exciting is exactly the same.

What's behind tomorrow's door?

The Curious Return of the Empty Advent Calendar

Perhaps the most interesting twist in the advent calendar story is that after manufacturers spent decades finding more elaborate things to put behind the doors, one increasingly useful format deliberately contains...

Nothing.

Fill-your-own advent calendars put the decision back into the hands of the person giving the calendar.

Twenty-four drawers, pockets or boxes can be filled with whatever suits the recipient.

For children that might mean sweets, small toys, stickers, stationery, coins, jokes or handwritten messages. Adults might receive chocolates, beauty products, tea bags or little personal gifts.

And there's no rule saying every compartment has to contain something bought from a shop.

A family could include:

• "Choose tonight's Christmas film"
• "Hot chocolate after school"
• "Bake Christmas biscuits"
• "Stay up 30 minutes later"
• "Christmas lights walk tonight"

Suddenly the advent calendar becomes less about 24 products and more about 24 little experiences.

For retailers, fill-your-own advent calendars also create an interesting opportunity because the calendar and its contents become two separate purchases. Small stocking fillers, pocket money toys, stationery, sweets and miniature gifts can all become potential advent fillers.

Why Small Things Feel More Exciting Behind a Door

There's something slightly strange about advent calendars.

Take a small toy and place it on a table. It's a small toy.

Put exactly the same toy behind a numbered door that can't be opened until December 14th and suddenly it becomes considerably more interesting.

Why?

Part of it is uncertainty.

Part is anticipation.

And part is the simple pleasure of revealing something hidden.

It's the same reason lucky dips, mystery bags, blind boxes and collectable surprises appeal to children. We don't simply enjoy receiving things; we enjoy discovering them.

An advent calendar stretches that discovery across almost an entire month.

That's also why the individual contents don't necessarily need to be expensive. Twenty-four enormous presents would rather defeat the object.

The pleasure comes from the repeated little reveal.

Not Every Advent Calendar Needs 24 Toys

With so much attention on increasingly extravagant advent calendars, it's easy to overlook the formats that have survived almost unchanged.

Traditional cardboard children's advent calendars still have a wonderfully nostalgic appeal.

There's something deliberately simple about finding a festive illustration behind a little paper door.

Advent candles take the idea in another direction altogether. Rather than opening anything, the passing days are marked as the candle gradually burns down towards Christmas.

And make-your-own advent calendars turn the countdown itself into a Christmas craft project.

These products serve quite different customers, but they're all based on the same idea: making the wait for Christmas visible.

One Tradition, Lots of Different Customers

This variety is particularly useful when choosing wholesale advent calendars for retail.

Not every customer wants the biggest or most expensive calendar on the shelf.

Some parents actively seek a non-chocolate advent calendar. Others like the nostalgia of a traditional picture calendar. Some want an activity they can personalise themselves, while others want an impressive toy or gift calendar that feels like a substantial present before Christmas has even arrived.

That means an advent-calendar display doesn't necessarily need twenty versions of the same idea.

A more interesting range might combine:

Traditional calendars
Affordable, recognisable and nostalgic.

Fill-your-own calendars
Reusable or personalised options for customers who want to choose the contents themselves.

Toy advent calendars
A daily surprise with something children can continue playing with afterwards.

Gift and jewellery calendars
Individual gifts that gradually build into a collection.

Make-your-own calendars
Part Christmas craft, part countdown.

Advent candles
A completely different interpretation of the same tradition.

The common thread isn't what's inside.

It's the countdown.

The Retail Calendar Starts Before the Advent Calendar

There is, however, one unusual thing about selling advent calendars.

They have one of the clearest deadlines in retail.

Nobody wants to discover their perfect 24-day advent calendar on December 19th.

For customers, the countdown begins on 1st December.

For retailers, it begins considerably earlier.

Advent calendars therefore need to be visible while customers are planning Christmas rather than when Christmas shopping reaches its frantic final stages.

That makes them rather different from ordinary stocking fillers and Christmas gifts, which can continue selling right up to Christmas Eve.

It's a useful distinction when planning seasonal stock: an advent calendar is a Christmas product, but its main selling window comes earlier than much of the rest of the festive range.

So What Comes Next?

Considering how far advent calendars have already travelled, predicting their next incarnation is probably unwise.

Perhaps technology will become more involved. Perhaps sustainability and reusable calendars will become increasingly important. Perhaps tastes will swing back towards simpler traditions.

But it's difficult to imagine the advent calendar itself disappearing.

That's because underneath all the changing fashions, packaging and products is an idea that hasn't really changed in generations.

Christmas is coming.

Children – and quite a few adults – are impatient.

And opening one little door makes waiting for tomorrow just a bit more fun.