I am a haphazard sort of bullet journaler, I have my bullet journal (currently housed in a Filofax pocket planner, but that might change soon, knowing me) around me all the time, but I only write in it sporadically during the day.
At night, however, I have it with me all the time. I sometimes do the only writing of the day at night.
I check off tasks I had planned the night before, write down my meals and the books I have read throughout the day, and I set up the next day.
I add stickers to empty spots on the page, and write in extra things I have done throughout the day.
This way, the bullet journal is a log book as well as a planner.
And I love these nightly sessions. I love to describe my day in short bullet points. It makes me feel so calm, to take stock like this and to get all the things that I have on my mind on paper.
It is the best!