I also keep a journal like that. I'm allready on a second volume though. I use plain ''dummy'' books, empty pages and a burgundy cover. I note down all the interesting things that happen in life.
I used to write in it on a weekly basis, hence why I allready have two. But now I prefer writing down only the truly striking things. That way it will cover more time once it is full.
I write about travelling, museums, artefacts, history and all that lovely stuff. I sometimes include pictures of objects or people. Locations I prefer to draw myself (while on the location).
Every page has a date and title on the top.
I'd say those journals are one of my most beloved posessions as they contain so many memories.