Team managers should till the soil with their teams.
Anything else is waste and waste must be rooted out.
Still it is hard.
Luke Melia wrote about how he performed as functional manager and dedicated 75% of his time pairing.
There are two tremendous challenges with this.
The first is limiting distractions in order to remain a reliable contributor.
Luke has tremendous reserves of focus and enthusiasm. As his manager, I did everything I could with our scrum master, Salim Divakaran, to support him, remove distractions and share workload.
The second challenge is being both the boss and a peer.
Luke recruited most of the team, he held weekly one on ones with each person, he insisted on unvarnished feedback, and is worthy of respect as both a peer and a manager.
So, here is the pattern: An experienced coach with people skills and authority over development practices pairing in with the developers. An experienced scrum master. Functional management residing in one or the other or divided up in some sensible and easily described way among the two of them.
This enables direct participation in the work, management attention to the team, and strategic contribution to the rest of the company.