Even if you think you know a word.
I do this all the time when I am reading and writing. I do it to double check that I am using a word in the right context, or to double check that I want to use this word in this context. Maybe by looking up the definition I will see a synonym that I like better. Or maybe I’ll learn a new definition / alternate use for that word. I make myself mini dictionaries in my journal and my notes app