There is a size at which a team that was working well starts to work less well, and I think the hard thing about it is that nothing visible changes. The people are the same. The work is the same. What changes is that the manager's attention, which was enough for eight people, is being spread across fifteen, and attention does not scale.
These are the challenges I think every growing team runs into. I am not sure there are answers to all of them. I am sure they are worth seeing early.
Attention gets rationed
At eight, a manager can know what everyone is working on, have a real one-to-one with each person, and notice when someone is struggling before they say so. At fifteen, that is arithmetic that no longer works. The one-to-ones get shorter or less frequent, the manager knows less about each piece of work, and the noticing happens later.
I think the honest response is to decide, on purpose, what the manager will stop doing, rather than doing all of it a little worse. That is uncomfortable because every one of those things felt like the job. Some of them have to become someone else's job.
Context gets expensive
On a small team, context is free. Everyone hears everything. As the team grows, the manager becomes the place context collects, and passing it on becomes a task in itself. The symptom is people finding out about a decision after the fact, or two people solving the same problem because neither knew about the other.
I have come to believe the fix is writing, and a habit of writing things down where the team can find them before anyone asks. It feels slower than telling people. It is the only thing that scales.
Decisions wait on one person
A growing team generates more decisions than one person can make, and if the manager is still making all of them, the decisions queue. The team does not say this. It just gets slower, and the manager, seeing the slowness, works harder, which makes the queue longer.
The challenge here is growing people who can decide. I think that means naming leads, giving them real decisions rather than recommendations, and accepting that they will decide some things differently. The alternative is a team whose speed is capped by one calendar.
Knowing when to split
At some size, the right answer is two teams rather than one bigger one, and I think the hard part is that the moment is never obvious. The team still works. Splitting it creates a seam, a second set of ceremonies, a boundary that has to be managed.
The signal I watch for is whether the team still shares a purpose that fits in a sentence. When the sentence needs a semicolon, when the team is really two groups who happen to attend the same standup, the split has already happened and only the structure has not caught up.
Where this stops being true
A team with strong leads already in place, or one doing work that naturally divides, can grow further before any of this bites. And some of what I have described is specific to a manager who started hands-on and is reluctant to let go, which is to say, it is specific to me. The challenges are real at any size. How soon they arrive depends on how willing the manager is to be less central.
Photo source: https://photos.robertstowe.com/dolomites