My EDD was 25th, she arrived in 26th in the end.
I had a 1st Christmas baby HEO just in case as it would be fine for sleeping even if no one else saw it. I also had bits for a stocking just in case - tiny sudocreme, tiny Vaseline, pack of bibs, sippy cup, small stuffed animal, etc - all things that we'd need anyway at home or in nappy bag but could combine for a stocking if she was already here.
I told DPs and DPILs that we were not travelling (2.5 hours away) and while most other years we stayed at home was a cook ourselves job, it was the only time I had Christmas dinner in my DGPs house as an adult (20minutes away in my city). So all I had to do was sit and chat (I slightly upset some people by standing stirring gravy but I was too antsy to sit still - I understood why a few hours later).
But Dh and I spent most of the day fairly low key - nice breakfast, mass in local church, long walk (waddle) on local pier, calls to family before some quiet relaxing time snuggled on the couch for a couple of hours, before going to DGPs house for the evening.
But we also had some nice bits and pieces bought in as well, just in case I wasn't up to going out or DD had already arrived and we were just getting home as a trio. (In which case, I may or may not have wanted to go to a big family gathering).
As it happened, the gathering in same DGPs' house with all my family (annual post-Christmas event) involving 21 people was a couple of days after we got home. And my other DGM was visiting my DAunt locally so there was a 15 person call to her house for tea and photos about 10 minutes the other direction first, before the dinner - which was a nice thought but all a bit much for me (and DD being passed around) by the end of the night!