Understand, calibration has nothing to do with your battery life. Calibration only makes the reporting of your battery's condition more accurate. Calibration is just the process of putting a complete cycle on your battery, making sure it's 100% drained, not 99.9% drained.... hence, the 5 hour wait after shutdown. You won't damage or kill a battery by failing to calibrate. You simply won't get accurate reporting of its health or charge level. You CAN harm a battery by failing to put cycles on it, by leaving it plugged in 100% of the time.
The recommendation to calibrate when you first get your Mac, as well as the recommendation to calibrate every month or two, are general recommendations. If you miss the "schedule" by a few days or weeks, there's no harm. Just calibrate it and you'll be fine.