Think of writing blogs as documenting what you have learned into a public repository.
Your articulation will help you make beautiful connections across books and essays you had encountered.
This public repository shall be helping everyone who comes across this.
There needs to be no strict schedule. Just when you come across a great insight or made a great connection and decided to publish it, do it. Or you can publish everything you learned from a book.
But the importance of publishing and articulating what you learned can't be overstated.