Until your company is fairly large (maybe 20 people?) document for yourself. It's your business, so you can do whatever you want, but I'd suggest writing things down that will help _you_ in three months when you have to look over something you did before.
With that in mind you should decide what you value. The small company teams I've worked on have exchanged virtually all knowledge verbally, and we would only ever draw whiteboard diagrams of things for new hires, which was convenient because the stuff seems to change as fast as the ink dries.
Until your company is fairly large (maybe 20 people?) document for yourself. It's your business, so you can do whatever you want, but I'd suggest writing things down that will help _you_ in three months when you have to look over something you did before.
With that in mind you should decide what you value. The small company teams I've worked on have exchanged virtually all knowledge verbally, and we would only ever draw whiteboard diagrams of things for new hires, which was convenient because the stuff seems to change as fast as the ink dries.