@Anonymous
Thanks! That adds the true requirement then if it is based on the month and day as well as the count of years.
So really, doing the year count and using the days is not helpful in this case. What is needed is the year difference and then a comparison to the month/day of the year. For that last part, I would use a leap year as the determining year so that if a person has a start date of 2/29, then the calculations would be correct.
The formula would be:
With({_start: DateValue(Service_Date_Field.Text), _end: Last_Day_Worked_Date_Box.SelectedDate},
Year(_end) - Year(_start) -1 +
If(DateDiff(Date(Year(2020), Month(_end), Day(_end)), Date(Year(2020), Month(_start), Day(_start)))>0, 0, 1)
)
Note in the above, 2020 is used as it is a leap year. It need not ever change, it is just reference for the month/day part.