> I am on the fence for HOUR_PER_DAY and MINUTE_PER_HOUR, because they never change, but they at least add a certain security if you chain them together. bar = lengthInSeconds * SECONDS_IN_MINUTE * MINUTES_IN_HOUR * DAYS_IN_YEAR.

Ideally, especially if you're using a strongly typed language, you should just use time-unit types (or at least macros or inlinable functions) for that: `fromSeconds(lengthInSeconds).toYears()`, lengthInSeconds.seconds.to_year, `SECONDS_TO_YEARS(lengthInSeconds)`, new TimeSpan(seconds=lengthInSeconds).toYears(), etc...)