Australia has purchased 59 refurbished American M-1 tanks for $8 million each (including lots of ancillary equipment and spares). The M-1A1 tanks will replace German Leopards, which are nearing the end of their useful life. The 59 tanks are enough for one tank battalion which, with the addition of two mechanized infantry battalions and some support units, would produce one mechanized brigade. This would be the largest unit Australia would be expected to send overseas. Australia, due to its size and location, does not anticipate being invaded by a hostile armored force. So the M-1s would be mainly for any overseas operations.
There are other reasons for getting M-1s. First, there is reputation. For fifteen years, the M-1 has demonstrated clear battlefield superiority. There is nothing on the horizon that can match it. Then there is the compatibility angle. Australia and the United States are close allies. If Australia gets into an overseas scrape, it will probably be as an American ally. Thus Australian M-1s would have an easier time getting supplies and spares. Another angle is that Australia might not even have to send its M-1s overseas. If the Australian mechanized brigade was relieving an American brigade, the Australians could, as American units currently do, just send the crews to man the tanks of the troops returning home.
The 59 Australian M-1s are expected to serve about twenty years.