Australian home loans use a standard amortisation formula: each repayment covers the interest accrued that period, with anything left over paid against the principal. Early on, almost all of the payment is interest. Late in the loan, almost all of it is principal.
Two levers do most of the work: the rate, which the RBA's cash rate steers, and the term, which most lenders cap at 30 years. A 1% rate change on a $650,000 loan over 30 years swings the monthly repayment by about $410.
Repayment frequency matters too. Switching from monthly to fortnightly while keeping the same amount works out to 13 monthly payments a year instead of 12 — quietly shaving years off the term and tens of thousands off the interest.