As you probably know, using epoch timestamps and adding/subtracting constant periods of time isn't accurate on the scale of months: February is a lot shorter than December. And then there are leap years and so on...

What you really want is something which works on the granularity of days and months, not seconds. You could write your own, but before you do that you'll probably want to check out the modules Date::Format, Date::Calc, Date::Parse, and maybe even Date::Tie. Date::Calc is good at doing date/time math that's actually correct, but it depends on receiving dates pre-parsed as YYYY, MM, DD, etc. Some of the other modules can get you the results Date::Calc is looking for.

Alan