Hmm - I obviously assume you know what you are doing.
And yes, I agree, I think as well that retirement stocks in NZ are still a great long term investment (hold some myself).
However during times when share prices world wide appear to be quite dear it might be a good idea to be careful with buying on margin account. If & when the next crash happens will the banks or brokers be quick to get their money back ... and nobody likes to be in a position where they need to realise losses because the banks force them to sell.
While I think that it is likely for retirement stocks to go up mid or long term - nobody can predict what is around the next corner - and if they happen to dip temporarily (like Ryman did after the GFC by more than 40%) - would your bank still be happy to extend your credit?
It is a dangerous world out there - and one of the things which caught recently my attention (there is somewhere a great post from Hoop) is that margin accounts are at peak values similar like short prior to previous crashes.
Anyway - all the best .... just take care with buying on margin account, particularly towards the end of a long bull cycle ...