bless you mirror man <| sep |> What I mean is all lending institutions have a cap at how long you can go interest only for on an owner occupied loan , a quick look shows CommBank is 10 years max , Westpac is 5 years max etc . Going interest only repayments when OP ' s intention is to buy an investment property in 5 years time means he would fully use Westpac ' s interest only period for his owner occupied and if life threw him a curve ball and he had to use redrawoffset to cover that cost he would be without interest only as an option at that time . In addition if interest only was fully utilised then the PIF repayments would be higher because of the monthsyears where he didn ' t make PIF payments . Again this is all worst case scenario but being realistic about interest only is important , especially when you are in a position to cover the PIF repayment comfortably .