Ron Jeffries has said "code never lies, comments sometimes do". What makes comments sometimes lie? Usually the reason is that we don't keep them up to date. In this blog post I have written about few commenting anti-patterns and how to avoid lying comments.
The most important thing for a software developer is his knowledge. Unfortunately it will expire sooner or later if we don't maintain and improve it. But problem is that we are often too busy to improve. Working on the important and non-urgent is one solution to improve even if you are busy.