We need to revturn to the pre-Republic Roman system of ten 28 day months and a liminal, unaccountable 90ish day period during the winter where dates don't exist. We need to have a high priest pulling apart bird guts to tell us when in March we can start counting days again. We need a system so subjective and variable that you occasionally need a 500 day year to reset everything either becuase of compounding error or because the priest in charge got murdered and no one replaced him for two months.