When DH and I first got together, we went to our own parents on the day, spending Christmas Eve, and Christmas night together. We then decided, once we got married, we would just alternate until we had kids.
Sadly my DM found out she was terminally ill in the September before we got married so that Christmas we spent at our house (DH, DM and me) and the one following our wedding and her death we had lunch at home just the 2 of us and visited his family at his parents at tea time.
Since then, we have always gone to SIL's who hosts for her parents, her brother, her husband (DH's brother) & their 3 kids, DH's sister (sometimes her husband comes along too), PIL, DH, me and DD! Her DM and I pitch in with prep and bringing dishes/dessert, etc.
This year will be the first Christmas since MiL died so I presume we'll be at SIL's as usual. But her mum is also terminally ill, so it will be a "play it by ear" situation in December. We have space to host other SIL & FIL, if SIL needs to be with her DM.
Luckily we all live within a 15 min drive from each other so it's easy to navigate and not take up chunks of the day in travelling.
I see my family (auntie, uncle and cousin) in the lead to Christmas when they come round for roast beef/turkey sandwiches