Mary Holm on investing  Mary Holm is a personal finance writer
Mary Holm: Planning for mortgage interest rises  As part of
diversification on your mortgage, have some of the loan
floating, so you can repay it without penalty if you suddenly
receive a windfall.  It's a recurring theme - mortgage interest
rates go up and down in seemingly random patterns while
borrowers try to work out what is the best or even just the
sensible option.  Is there a sensible option? Maybe a rule of
thumb to follow? While interest rates are being talked up should
I grab the lowest, longest term possible, even if that means
paying more in the short term?  Currently I am lucky enough to
have about six months left of a 3.74 per cent loan of $220,000
on a $450,000 house (lucky being a relative word for
Cantabrians). Would I be wiser to fix at least some of it for
say five years at about 7 per cent, or just hold tight?  I'm
female, single, approaching 60, earn an average income and,
apart from KiwiSaver, my house is my only asset.  Th