Rent charges are usually 52 weeks or 12 months. Use the flat renting analogy if it helps.
Some salons offer a 1-2 week holiday, but usually only if they want to close the salon over Christmas break. Obviously, you can't charge them rent if they can't actually go in and work.
That's the downside if you were doing percentage split and they chose not to come in. Not much you could do in that instance.