We open a family gift on Christmas Eve. Normally it will be a family movie and some popcorn. Everyt else is for the big day and this year we have great grandpa here for thw kids, might be the only one they get with him.
In laws on eve. My parents xmas day. We started a tradition of our own family on new years. Gives my wife and I the opportunity to see what kids did and didn't get, make decisions from there.
When I was a kid, we did most presents on eve at mom's parents. Fewer the next day at dad's parents.