When the kids lived at home they were always allowed to open one present from under the tree before they went to bed.
The rest was normally any time after 5 the next morning
Now we always have at least two Xmas days due to family circumstances.
This year it is three, so we will exchange gifts with son and daughter
in law on Sunday before our first Xmas dinner.
She goes back to California early Monday morning.
Then it’s hubby, son and myself for the 25th so we will open any other presents and stocking.
Daughter and partner are here from the 27th onwards so we will celebrate Xmas day on the Sunday again, exchange gifts and stockings and the full on Xmas dinner again.