Working as a zookeeper requires you to be passionate about animals and wildlife conservation. You often spend more time with the animals than other zoo employees, getting to know their habits and personalities. This helps you determine when the animals are healthy or whether they need veterinary care, a vital role of primary caregivers.
So on average the number of days between two similar phases (e.g. between one full moon and the next full moon) is about 29.531 days. This period is referred to as a lunation, lunar month, or synodic month.
The most recent blue Moon occurred in August 2012. On average, there's a Blue Moon about every 33 months. Blue Moons are rare because the Moon is full every 29 and a half days, so the timing has to be just right to squeeze two full Moons into a calendar month. The timing has to be really precise to fit two Blue Moons into a single year.