"You might be able to afford a $600,000 house, but it may make more financial sense to buy something cheaper to start with, rather than heft all your income into a mortgage that has a limited return," he said.
"A good thing to remember is that your first home is not your dream home. That comes later in the piece."
O'Leary said would-be buyers shouldn't set their heart on a property until they had their finance confirmed.
Childhood sweethearts Joe and Maria Riley echoed O'Leary's sentiments, saying: "Sort your finances a good time before you start looking. "The first home isn't your only home. It doesn't have to be forever so don't be too fussy and don't expect to just find your dream home straight away."
The Hastings-based couple have a budget of just over $200,000.
Hamilton couple Monique Wanner and Chris Forsythe joined the hunt after finding out their rental property was in the path of the new Waikato expressway. The new highway will make buying a home in Hamilton and commuting north a more attractive option for refugees from the Auckland housing market. This means they will be up against some serious competition.
Despite feeling the pressure of rising prices, the couple emphasised the importance of due diligence when considering a home.
"The market is pushing harder and faster but you are only setting yourself up for a fall by not researching, getting a builder report etc," they said. "Unless you have the money to get yourself out of a leaky home nightmare, don't rush things. The right home will come."
Further south, returning Christchurch resident Martin Thompson has had to come to terms with post-earthquake changes to his home town and the effects of the rebuild on the local housing market.
After 10 years overseas Thompson has returned to put down roots with his English girlfriend, Helena Turner.
Thompson said first-time buyers needed to stay within their means.
"Buy the worst house on the street and do it up, if you're that way inclined," he said. "Don't buy the best house on the street."
"Do your homework and put your name down with as many real estate agents as possible so you are on their mailing list to send you new listings or to advise you of properties before they even come on the market to the public."
Young British couple Will Hearn and Grace Livock have decided to buy a home in Queenstown and said it would be their biggest commitment to date. To them it is bigger than marriage.
"Shop around for the best mortgage you can," they said. "Go into all the banks and see who can give you the best rates.
"Don't be afraid to go to open homes. The more houses you see the more you will know what you are really looking for."
• House Hunt airs on TV One, Sundays 8pm.
