Hi, I am looking for a way to enter time durations involving years and months.  Ideally in the format YY-MM.  But when I set the format to such a format and try to enter “6 months” as 00-06, it is interpreted as 2000-06 (displayed as 00-06 though), whereas adding this date to another date adds another 100 years, because LibreOffice’s epoch seems to be 1900-01-01.
So, how can I manually enter durations and visually see if they were entered correctly?
Note: As a programmer I know that working with times is a PITA, always.