A practical list that keeps the box affordable and stops it competing with Christmas morning.

Now, let me tell you something about Christmas Eve boxes, dear. They started as a lovely small idea and have quietly turned into a second Christmas for some families, which was never the point.
Done well, a Christmas Eve box does one job: it fills the difficult hours between dinner and sleep. Here is how to build one that helps.
Everything in the box should be usable that night. That is the whole design principle, and it solves most of the questions people have.
A toy they want to play with for three days is a Christmas morning present that has arrived early. Pyjamas, a film, and hot chocolate are a Christmas Eve box. The difference is whether it fills the evening or competes with the next day.
Eight things is generous. Five is plenty.
Toddlers want texture and repetition. Pyjamas, one board book, and something to hold. Keep it to three items, because more becomes overwhelming rather than exciting.
Ages four to seven are the sweet spot. This is the age where the whole box gets used properly. Add the making activity and the reindeer food.
Ages eight to eleven start to notice value. Swap toys for experiences: a card game to play with the family, permission to stay up thirty minutes later, or a film chosen by them rather than for them.
Teenagers mostly want to be included without being condescended to. Pyjamas, snacks, and a genuine say in the evening.
A Christmas Eve box does not need a box. A pillowcase, a gift bag or a reusable tote works exactly as well, and children do not notice the container after the first thirty seconds.
Pyjamas bought in the January sales cost a third of what they do in December. The book can come from a charity shop. The hot chocolate is hot chocolate.
If the box is costing more than a modest amount per child, it has stopped being a Christmas Eve box and become an extra present, and next year the expectation will be higher again.
After dinner, not first thing. The box exists to fill the evening, so opening it at nine in the morning removes its only function and leaves you with a long day and nothing left to do.
The item families tell us works best is not an object at all. A short call with Santa on Christmas Eve, slipped into the evening, gives the box a moment nothing physical matches, and it costs nothing to store afterwards.
If you would like to include one, you can arrange it at Chats with Santa.
Anything with a lot of small pieces, anything loud, and anything that needs charging. You are trying to move the evening towards sleep, not away from it. Ask me how I know.
The best Christmas Eve boxes are small, cheap and entirely about the evening they belong to. Pyjamas, a story, something warm to drink, and something to do with their hands.
Get those four right and you will have a calm house by nine, which is the real gift.