For firefighters in Germany this is, more or less, defined to be 5.
A group (which is one of the pre-defined tactial units) consists of 9 people: The leader, three troops of two, one machinist, one "Melder" (kind of the guy/girl for "special tasks", helping with whatever is necessary).
The leader commands the troop leaders, machinist and "Melder".
This is expected and taught as the amount of people you can actively manage and take care of in stressful situations like deployments.
edit: for larger deployments you'll have platoon leaders which will command a number of group leaders. for even larger deployments there'll be another layer of command so each platoon leader will only have to lead a set number of group leaders, too.
This is going to be true of more professional military specialists as well. A Special Forces team will have an officer leading 4 sergeants - med, comms, weapons, and construction(/destruction). This is more of an exception rather than the rule though.
I don't see how people are supposed to reasonably manage 10+ reports. At that point they are just a figurehead.
> I don't see how people are supposed to reasonably manage 10+ reports.
True! I'm leading 5 people at work and I find that enough most of the time, as I still have projects that I'm actively working on, too.
If there are more people to come, I'll ask to integrate some kind of "team lead" for some of them, before all the work I do is micromanage and respond to mails.
For firefighters in Germany this is, more or less, defined to be 5.
A group (which is one of the pre-defined tactial units) consists of 9 people: The leader, three troops of two, one machinist, one "Melder" (kind of the guy/girl for "special tasks", helping with whatever is necessary).
The leader commands the troop leaders, machinist and "Melder".
This is expected and taught as the amount of people you can actively manage and take care of in stressful situations like deployments.
edit: for larger deployments you'll have platoon leaders which will command a number of group leaders. for even larger deployments there'll be another layer of command so each platoon leader will only have to lead a set number of group leaders, too.