Many people suggest that you can increase your job security by becoming an "irreplaceable" member of the team, by becoming a domain expert (the article's "go-to guy"). But my boss advised the opposite: if you cannot be replaced, then you are stuck. Management may prevent you from switching teams or being promoted to a different position if no one else can cover your irreplaceable knowledge. And you will be the one fighting all the fires on nights and weekend. Always ensure you have an "escape plan" by sharing your knowledge and grooming your possible successors.

And these days, there is no such thing as job security. If your employer cancels your team's product, you will still lose your "irreplaceable" job.