Telstra offers new contract that allows an upgrade after a year.

One of the great things about having a mobile phone on a contract is that you get a shiny new phone for free*every time you renew your contract. The problem is that on a standard 24 month contract with Telstra that only happens (obviously) every 24 months and in 2 years your phone is so out of date it feels like you're making a call with a baked-bean can and a piece of string compared to what's currently available.

Shortly, Telstra will be offering an option to upgrade half way through the contract to a new phone, it does cost extra for the privilege and looks like you have to return the old phone "undamaged and in good working order". (I'm not too sure what that means, as always check the fine print)

See the link below for more details and check it out before you purchase your next phone under contract (preferably a Windows phone):
http://www.itwire.com/your-it-news/mobility/63220-telstra-offers-new-phones-after-a-year-–-but-you-pay-for-it