Are shared bank accounts and noses jointly to the grindstone the norm or are today's young couples opting for ''flatmates with benefits'' set-ups and indefinite prolongation of their spendthrift 20s?

Digital strategist Sam Zivot, 30, and Andrea, a 27-year-old doctor (pictured), married a year ago after a 10-year relationship.

While their affairs are intermingled - as the primary breadwinner for the past four years Sam covered the bigger bills, while Andrea's parents supported her studies - the two maintain separate accounts and savings.

Gen Ys - those born between 1980 and the mid-'90s - comprise the bulk of couples tying the knot in Australia.

Of the 121,752 marriages registered by the Australian Bureau of Statistics in 2011, almost 72 per cent were first-timers. The median age at first marriage was 29.7 years for men and 28 for women.

Zivot believes financial autonomy is a hallmark of many Gen Y relationships, however long term and committed.

'''What's mine is ours' is not as prevalent,'' he says.

''When you've had and controlled your own finances for so long, getting to the point where you're comfortable completely pooling it is a big step … It's almost like we manage our personal budgets in some ways, rather than completely sharing.''

This will likely change as the pair shake down into a double-income, no-kids groove, Zivot says, although he admits to some apprehension.

''I have been fortunate to accumulate a lot of savings. To tap someone into that is a mental step.''

Financial planner at PSK in Sydney, James Gerrard, says Zivot is atypical of his demographic. Few of the Gen Ys he advises are worried about ceding control of their savings to their significant other because it's rare for them to have any.

The couples Gerrard has seen blended their finances about two years in and did so with few reservations because they had few assets.

Typically, they have maintained personal accounts but set up a joint savings account or inherited each other's debts.

Many Gen Ys reach their early 30s with ''very concerning'' levels of the latter and a ''much lower regard for savings than the [Gen] Xs and boomers'', Gerrard says.

Some couples have spent 10 years together and accumulated nothing but credit card debts, loans, leases and household goods on interest-free plans.

The latest figures from credit-reporting agency Veda show Gen Ys are responsible for 60 per cent of defaults across all accounts types, up 5.3 per cent in the past three years.

''They feel like they can never buy a home so they get disheartened and focus on just enjoying themselves,'' Gerrard says.

This includes spending lavishly on things such as restaurant meals, holidays and technology items.

Gerrard's advice often consists of a remedial lesson in budgeting and the establishment of a regular savings plan.

Psychologist and founder of the advertising agency Naked Communications Adam Ferrier says the practice doesn't come easy.

Hedonistic behaviour and a sense of instant gratification are the hallmarks of Gen Y - and the same applies to their finances, Ferrier says.

Mercer regional leader for financial advice Michelle Smith says the instant approach extends to the way Gen Y couples seek advice.

While older folk look for holistic input, the young are in the market for solutions.

''They're often aspirational and financially savvy and will come with information that they've had from the net,'' Smith says.

''They want you to help them instantly.''

Most commonly they're focused on housing affordability and whether they should aim to buy their own home or rent long term, Smith says.

''They might want to buy in five years and are looking for a road map.''