How do we pay exempt employees for partial days?

Q: “At a payroll seminar, it was stated that an exempt employee must take vacation time in 8-hour segments, and if they work even a half hour during that day, they must be paid for the whole day. However, it was then mentioned that if you want the exempt person to be able to take vacation time in 1-hour increments, your policy must state that. Is this true? Does the exempt vacation policy need to be the same as the nonexempt?” – Sandy, Nebraska