I've read in a few places (including on here) that when considering taking on more debt you should ensure that you can still service all debt at an interest of 8% (some say 10%, but 8% seems to be more common). I've just knocked up a little spreadsheet to calculate my 2 existing loans plus a proposed third, with a running tally of what the repayments would be based on a climbing interest rate. Assuming no changes in wages or increases in rents, I would probably top out at a little over 6%. That's got me a little nervous about buying another property, but even without the additional property I still wouldn't be able to hold much past 7%. This will all change in about 4 years time when my wife goes back to work (we're acquiring liabilities, aka kids at the moment). Is this risky? Am I in the minority here? Considering no increase in rent (i.e. today) and I/O payments across all loans, what's your 'breaking point' in terms of interest rate (I'm sure there's a better term for this).