To Blue hauler...
Yes, in many aviation jurisdictions, a medical and an I/R have a "30 day" grace period, ie, you can renew up to 30 before and up to 30 days after the calendar date - this "grace period" is not shown on the certifiacte, but provision for it is contained in the State's Rules - not relevant to the MR debate as such, but a date on a piece of paper is NOT the sole determinate, in all cases, of expiry of an MR or equivalent. The proposed CASA rules, more internationally aligned and up to date, will in fact be reflecting this approach.