Once daily, right after work. It doesn’t need to be a long entry, just noting significant events, how you are feeling, something going well, and something you aim to change is enough.
Every Day, 1-4 hours. I uust wake up and plan my day in my bullet journal but if I have a specific topic i want to journal about in a random time of day, I will.
Personally, I currently write once a day about several categories. I use graph paper notebooks and bulletpoint techniques that you can easily find examples of online shared by others. I use the time for deep work challenge to accomplish this, paired with the journal writing challenge to give myself sufficient time. There's several challenges within fabulous for topics to journal about that you can explore.