If no expiry date is set, will monthly leave accrual keep building year after year?

If no expiry date is set, will monthly leave accrual keep building year after year?

We would like to setup a leave system that an employee accrues vacation days each month up to a certain amount a year ex. 10 a year. At the end of each calendar year, only 5 days can roll over. If we do not set an expiry date, but have rollover enabled and set to 5 days, will the vacation days reset at the end of each calendar year, or will they keep accumulating?