I've been keeping an almost daily journal since the new year, though I've been journaling regularly for almost three years now. I mostly record the days events and use it to sort out problems I'm facing. My past journals especially are helpful to look at past thinking and emotional patterns. Finally, I use my journal to help remember writing ideas, either from real life, or just recording rudimentary ideas which may take me a few days to develop into something I can actually write. I also keep a (homemade) pocket notebook. It pretty much has everything besides the steady record of my life. From poem parts to story titles to to-do and shopping lists, from room design land to phone numbers. It's always with me, so it sees a lot of different uses.