Your team has grown from six people to fourteen. How do you reorganize?

Split along the work, not along the org chart. Draw the boundary where ownership is genuinely separable (distinct services, distinct customer surfaces) so each team has its own mission, its own on call and few cross team dependencies for routine work. Keep both teams able to ship end to end, choose the second lead deliberately, and plan for a temporary drop in throughput during the transition.

Fourteen means my one to ones are shallow and standup is theater with eleven people listening to two, so the trigger is already there. The important decision is where the line goes. I look at where the work actually clusters over the last two quarters: which parts of the system change together, which pairs of people talk constantly, where a handoff already exists in practice. Splitting by seniority or by who gets on with whom produces two teams that need each other for every ticket, which is worse than one oversized team. In my last split we drew the line between the customer facing product surface and the platform and data pipeline, because those had different stakeholders, different release cadence and almost no shared code paths. On leadership, I would rather grow somebody internally who already has the team's trust and back them properly than parachute in a stranger. And I tell my own leadership to expect a quarter of reduced throughput, because pretending otherwise turns a normal transition cost into a perceived failure.