Somewhere there's a balance

When working in a team you need to improve both the quality of your code as well as the quality of your teammates.

The highest yield comes from having your most experienced teach your teammates. Your teammates make better decisions and write better code. However, it is the most time consuming and incremental. (I guess this is why people say only hire the top 10%, by the way who are the other 90% working for?).

The fastest yield comes from code improvements. By dedicating experienced resources to improving code quality you get immediate results.

The trick is the people you haven't brought up to speed will soon be in that code.

Somewhere there's a balance.