Typically, paid time off is granted in units of days. Also typically, upon ending ones employment, the employer pays the employee the value of his/her unused vacation days. If the payroll schedule is twice a month, how is the value of a day calculated since different months have different numbers of work days?
Not every company calculates this the same way. Not every company pays out unused vacation. This is question for your local HR or you can look in your employee handbook which should describe the policy.