Yttrium iron garnet Fe3Y5O12 (YIG) is the material of choice for spin Hall related effects, magnonics, inter alia and has been used in microwave applications for many years. This is mainly due to two properties: a) YIG is a wide band-gap insulator, so it has no free electrons to contribute to the thermal conductivity in the Seebeck effect or to shunt the electrical signal in the high spin orbit metals used to measure the inverse spin Hall effect, and b) YIG has a very small Gilbert damping (~10-4) with a narrow resonant peak.Despite its popularity the magnetic properties of thin film YIG are not understood. Our group has conducted a comprehensive study of this topic, and have three further questions we wish to answer.