Teachers often describe a child who copes well all day. Parents often describe the same child falling apart the second they walk through the door. Both are telling the truth.
Managing a full day of noise, instructions, other children and unfamiliar demands takes real effort, and a child spends most of what they have holding it together in a place that expects it of them. Home is where the holding-together is allowed to stop, which is exactly why it stops there, not at school.
Questions, demands, and even well-meant excitement in the first minutes after pickup ask for more from a child who has nothing left to give. A quiet transition — a snack, low demands, no "how was your day" — before anything else is asked of them tends to shorten the meltdown rather than trigger a bigger one.
A child falling apart at home and coping at school is often a sign the coping is working, not failing — it just has a cost, and home is where the bill comes due. That said, it is worth mentioning to the teacher regardless, since they may not see this side of the day at all.
Not necessarily, but it is worth a direct, calm conversation with the teacher either way, since they genuinely may not know this is happening once your child leaves the building.
There is no fixed length. Watch your child; some need ten minutes, some need an hour before they can handle a question or a demand.
That is a decision for your family and, where relevant, the school. A child arriving home already spent is rarely in a position to do their best work immediately, and that is worth factoring into when the harder tasks happen.
Part of our guide to Big feelings & belonging.