Any company with reasonably involved processes (read: more than three steps) should have clearly documented SOPs, policies and process documentation. This has nothing to do with the level people are at. I'm at senior level and sure as shit don't remember every detail of something that was verbally communicated to me months ago unless I do it every single day, and even that's error-prone. I write step by step instructions on processes for myself and everyone else.

Benefits of this approach:

• It's not stuck in my or anyone else's head, but clearly spelled out
• people can follow the process again and again, no matter how much time passes between each time - you'd be surprised how much people forget if they don't do something on a daily basis
• clear documentation removes doubt
• clear documentation is beneficial to newly onboarded staff. Nobody gives them a half-baked version scraped together from memory fragments
• people can point out potential issues with the process, and the documentation can be amended/updated
• I myself can go back to it if I have even the slightest amount of doubt on a detail.

Drawbacks of this approach:

• someone has to write the document
• someone has to maintain it