This is one you learn early if you work for a smallish company:

If you're staffing a project, make sure you have enough people who are adaptable to several types of work.

This is extremely true. In a small organisation there are quite simply more kinds of tasks than there are people to do it, so everybody (absolutely everybody) needs adaptability and flexibility as a basic skill.
People who think of specialization as their professional quality and take pride in their single minded focus on their core competences to the point of saying no to go outside that core might be suited to a bigger organization, but in a small group, when problems change all the time, they're just baggage.

The difficulty comes when you want to migrate that small, adaptable organization to a big, efficient organization. Then all of a sudden the skillset you needed in the little organization becomes a liability and the proud specialists are needed exactly because of the uncompromising attitude that made them unfit for the little team.