Hiring a Senior Engineer - What's the Bus Factor?

In this episode, Dave and Jamison answer these questions:

1. I’ve joined a team at a small startup and our team lead has mentioned in passing a few times about a developer they used to have but had to let go. Not in a malicious way but just as a matter of fact when it’s come up organically. Now it’s eating at me because I’m not sure if I’ll ever go down that path and I want to know what they did so I can avoid the same fate. I’ve always been a top performer at other companies but now I’m wondering if this would be the one place where standards are higher than what I’m used to. I really like it here and don’t want to lose my spot. Realistically my fear isn’t that I’d get fired in my first six months but more that I would fail to respond to constructive feedback over the course of a year and end up getting let go in the same manner. Do you have any advice?

2. Hello! Long time lurker, first time question server.

   I am an intermediate software engineer and I work on a team that has a really tenured senior engineer. His attention is often required for a lot of things and the team can sometimes get blocked by him being pulled into many different directions.

   As someone that is trying to grow into a senior engineer myself, what are some ways to take some of the load off of him and improve the bus factor?