Excessive staff turnover - “churn” - is an indication that things are not well in your business.
Low churn is also not good – your business will stagnate without new people.
But a degree of churn is ideal.
It gives the opportunity to hire in people with new ideas.
Keep things fresh.
New ways of doing things.
You can hire people with less experience, but with great potential (of course you have to make sure you are set up to make the most of that potential).
You can hire people with a ton of experience who can bring a lot to the business.
How much churn? There is no absolute number here, but 10% is widely recognised as a good figure.
Some churn is good.