On the job training? Heresy! Shun the unbeliever, shun!

In my own current position, I would not have gotten the job if they had interviewed me then like they interview new hires now.

Don't know how to find and recover active but deleted files? Goodbye. Don't know how to follow strace around a distributed environment? See ya. No idea how the elevator works? Why are you even applying?

I know how to do all of those things now, because I asked questions of my colleagues and the internet. I'm now the lead developer, not because I knew everything coming in, but because I am able to learn.

I don't want my employees to have to learn everything just-in-time. By that logic, the people you hire wouldn't need to know anything. In addition, they don't know what they don't know, so they may not even know that they need a btree index.

The truth of the matter is that, for most of us, when faced with a problem we work with what we know. If you ensure breadth of knowledge, you can get better at each aspect, but if you only know a few fundamental ideas, that means that you have to be capable of looking at a problem and rediscovering the right data structure to handle it with. Essentially, you have to be as smart as the guys who came up with it in the first place and more. Better to know the data structures and how they work.

Recognition is easier than rediscovery.