Before I worked for a web development company, I asked a lot of questions of friends who were working as developers for tips about being good at your job.

One answer I got was:

"Always make the employers beg for your competencies. Prove to them that you are the best and you cannot be replaced. While keeping the status quo, hold your employers hostage where if one day they remove your from the job or task, no one else will be able to do your job."

How true is this statement?