Staff turnover
You train someone, they grow in skill and confidence, and then they leave. Sometimes it is for a competitor, sometimes for their own chair. Sometimes they stay but stop growing. Either way, a departure takes skills, clients and the time you invested with it.
Development that only lives in your head and on the salon floor is hard to pass on and hard to keep.
To sit with: What do I do today to develop my team, and what happens to that investment when someone leaves?