How long do you plan in advance for a homebrew campaign?

I don‘t know if you‘ve answered this before. But, how long/detailed do you plan in advance for a homebrew campaign? Do you write that planning in your campaign notes (characters, locations, etc) or is it a separate document, like you use a published adventure? #dnd As little as possible. Usually a brief outline and a general goal or path and then I focus on the stuff I need for the next adventure.

— SlyFlourish.com (@SlyFlourish) July 30, 2021