Throughout the year we keep writing in it, things we learnt, discords we had and how we resolved them, recipes I experimented with and we loved, random thoughts; basically anything and everything. And that little diary becomes an embodiment of that year.
I would also like to point out the manual labor and writing into it and not using an obsidian++-AI-auto-categorizer-3000 is simply because it feels like it's worth something, it's a nice little routine we have at the start of every year, and it's really fun reading these from 2-3 years back. Also the kids will have some really interesting reading a few years down the line.
I imagine a future where this becomes a family tradition that transcends time, knowledge from different generations, living different lives all nicely recorded in these codices. Something about this whole thing feels really beautiful to me.