I used to journal regularly. It was my routine that before bed I'd jot down my thoughts. Anyone who knows me knows that my writing is nigh illegible when I write fast, but I didn't write it in order to read it again later, but just to get the thoughts out of my head. It really helped me to sleep, actually.
Since having kids, I've largely dropped this habit. When the kids are little, I often end up falling asleep with them. I also tend to read before bed instead, since I can easily do that whilst nursing Charlotte.
My parents gave me a beautiful leather journal a couple of years ago, but even that hasn't induced me to journal regularly again. However, I'm not putting it to good use again. Since I'm staying off the computer more, I started using part of the journal to jot down my thoughts or reminders during the day. I've decided to use another section of it to jot down all the prayer requests I come across so I can be better at remembering them to God. I often forget the specific requests when I'm before Jesus in the Eucharist, and while I know He knows what they are, it will be nice to bring the journal before Him. Hopefully I can just remember to keep it with me so I can write down requests and bring them before God.