&gt; Knowledge workers aren&#x27;t cogs, they&#x27;re part of a team. You shouldn&#x27;t expect that you can easily find replacement people with exactly the same skillset and propensity as someone else to make up the gap that an absence makes in a team. Nor  should you expect that the proper way to grow a team is by cloning the skills of some other existing member of the team. A team works cooperatively, and their skills, talents, experience play off one another to gel together into some sort of mechanism that is capable of doing stuff.<p>Great comment, I totally agree that taking a wholly mechanistic view of how individuals and teams work is an error. You can&#x27;t account for all the &#x27;magic&#x27; that make some teams function in ways that are more than the individual parts.<p>Of course, you&#x27;re striking at an underlying fear for managers. Our jobs are to make things work immaterial of the individuals: positively a managers job is to make the system of people&#x2F;process&#x2F;systems work, and negatively to make sure that no individual should be so indispensable for the project&#x2F;department&#x2F;organisation. This mechanistic view generally works because most roles are 90% perspiration and 10% inspiration, as the saying goes.<p>Perhaps a good mix is that when a hole is created in the team, to look at the situation holistically. As the short-list of candidates is drawn-up consider how they could fit into the mix, and how they would be additive - not the same as previously, but a new opportunity - like a new ingredient, rather than a replacement cog. It reinforces the idea of having more peers from the group involved in the hiring as this could open up a range of opinions on how the mix could change.