If you say that someone or something is indispensable, you mean that they are absolutely essential and other people or things cannot function without them. In your line of work, you may feel that you can be disposed of easily; may it be through simple or complex reasons. This indicates that you may need some guidance on how to gain or retain indispensability through knowing someone`s mindset.
A person can always complete or achieve a goal even though they do not have all the necessary people or tools for it. Which boils down to preference, trust, or comfortability into a certain person or object.
Let us go to chess as an example. I have played chess for many years and I always needed to have my queen with me. All my strategies involved that piece and I felt that I automatically lose the game without it.
Thinking about the scenario, since the queen had the most moves, I relied heavily and built my strategies upon it even though I know myself that there are quintillion more combinations that I can create with what I have left. But it wouldn`t be the same, and my satisfaction points to a low.
Incorporating that concept to work, I just realized being there doing what you can only do for that person and your constant presence prove as an effective way to be indispensable. Do what you do best as much as possible and be a preference to them, be a queen.