Should I get a NZ phone number?

If you want to save money – yes. Unless you have an extra-special add-on deal or set-up with your home mobile network you will almost certainly be looking at paying a minimum charge per day which will add up to scary amounts over a month.

Additionally, even if you are prepared to throw your money away on the most expensive way of doing things other people who want to call you might not be quite so ready to waste their cash. Calling your overseas number is going to be too expensive for them so you could miss out with potential employees, new buddies you've just met and so on.

If you are going to be in New Zealand for a while it makes more sense budget-wise to either get a New Zealand phone and plan or buy a SIM to use in your existing phone if it is unlocked and compatible.

There are even ways to get round a locked SIM phone, most typically by paying a fee to your network provider or a phone unlocking service. New Zealand network providers all have advice re the compatibility issue on their websites and in stores. Skinny (which piggybacks off Spark) even has a compatibility test you can run directly through their website.