One day I read something on Facebook.
Ever since then, I made up my mind to journal my daily thoughts, no matter how tired I was at the end of the day, or how boring I felt my day was. (I used to do this almost everyday while in school/college)
I must say, it's week two and the pages of my notebook are slowly getting filled.
If you ask me, I really have no solid answer to the benefits of journaling, but writing is therapeutic for me. I find it such a pleasure to pen down what I go through in words. I am a nerd.
Also if you're living with Jesus I implore you to keep a journal of your walk with him. Write your rants, your gratitude, your dilemmas, your prayers. It will help you keep track of your faith.