I stopped dressing up on Christmas day when grandchildren came along, as I invariably spend much of the day on the floor playing with them, which is a lot easier to do in trousers - plus when I'm not playing, I am probably cooking!
When my own children were young, I had no problem doing those things in lovely dresses, but somewhere between them growing up and grandchildren arriving, I lost that ability.
That said, I won't be wearing scruffy clothes on Christmas day (though I might if OH and I were spending it alone), but nor do I dress up like I did in the past.
There will only be one grandchild present this Christmas, because the others are school age and mixing with a lot of people, meaning that we have no close contact with them at the moment, but I know I will be spending as much time on the floor playing as ever. Comfort and practicality first for me!