In New Zealand it's considered normal to share a house until you have a long term partner who you move in with, then you find your own house.
I know people in their 30's who still share a house or apartment. It's a social thing as much as a financial thing, your roommates are like platonic partners.
People always ask me how I managed to live like that, but they don't realise that you tend to adapt to your living conditions fairly quickly. If you can manage a couple of months, you can manage a year.
It's actually weird for me to live in a house with only a couple of other people now. I got so used to having people to hang out with practically on tap. There's always somebody to drink with, or watch a movie with, or snuggle up next to. It's strange for me to come home from work to an empty house.