A lender's yes is not your yes.

A lender starts with your income before tax, takes tax out, subtracts what already goes out each month including the limit on every credit card whether or not you owe anything on it, and treats what is left as capacity to repay. Then it stress tests that capacity against an interest rate several percentage points above the one you would actually be offered, so the loan still holds if rates rise.

That process produces a maximum, and a maximum is a different thing from a recommendation. Borrowing every dollar a lender will lend leaves no room for the year your car dies, your hours are cut, or your household grows. A number you can carry with room left over is not a smaller ambition, it is a more durable one.

Once the loan settles, the repayment arrives every month and so does everything else: council rates, water, building insurance, body corporate levies if it is a unit or a townhouse, and maintenance on a building that will not stop needing it. A home that is affordable on the repayment and unaffordable on the running costs is still unaffordable, and the listing will not tell you which one you are looking at.

Location does the same thing quietly. A cheaper home an hour further out can cost more once you price the second car, the fuel and the tolls, and it takes ten hours a week of your life on top. That is not an argument against buying further out. It is an argument for putting that number in the same column as the price instead of a different one.

A borrowing power figure answers what you could borrow. It cannot answer whether you should buy this. The second question needs the price you would actually pay, the duty and buying costs that attach to it, what survives of your savings afterwards, and how the home lines up against what you and anyone buying with you said mattered. Those are the parts that differ from one home to the next.

You give the address and the price you are considering, answer a handful of questions about what matters to you, and get a read on how that particular home lines up, with the reasoning shown rather than one score to trust blindly. Where Byrz could not check something, it says so instead of guessing, and it never puts a price on the home.

In rough order: the price you settle on, whether a duty concession applies to you, how much of your savings survives the buying costs, the interest rate at the moment you fix your position, and any debt you carry, especially credit card limits you never use. Four of those five can be changed before you make an offer. The last one is the one people do not realise is changeable at all: a lender counts the LIMIT on a card, not the balance, so a card you have not touched in two years is still reducing the loan you can be offered until you close it.