Luke,
On one of my current houses, i pay $850 a month in interest. Keep in mind Canberra is, on average, an expensive place to live.
Since this will be an investment property i am at the moment paying interest only, offsetting my mortgage with savings till i can afford another house. I downgraded from a 3 bedroom to a 2 bedroom as the baby is due soon, saving me more money. Most people are not willing to do this, they want 3 bedrooms because kid. If you ignore my other house all together:
i pay $850 a month, going rate for my house is around 300-330 a week. Ill go with 300 a week.
That's $1200 a month in rent money for a 2 bedroom house. I'm saving $350 a month on what my "rent" would be. Effectively it is cheaper to buy than it is to rent!
That $350 a month can go towards the mortgage more, or towards said gearbox that breaks or anything else.
Point is, 30k is around the deposit for an entry level house (a little bit more)
TL;DR There is no housing affordability issue in Australia.
TL;DR It's worth saving the cash.