Do you have control of the security of your premises?
How many people or organisations may have keys to your front door?
The Landlord and the Real estate property manager? Yes, if you are renting, this is controlled by Victorian state law.
The neighbours? Yes, if you have made that decision but NOT if they were given out by the previous owner/tenant.
The previous owner/tenant? No!
The previous owners/tenants X or flat mate? Definitely not!
Anyone who knows where the hidden key is from years ago? I dont think so!
People coming and going from your new premises will not trigger protective responses from the neighbours.
It maybe a good idea to have the locks changed even before you start moving your items in, especially if you are moving in stages and there is no one around to keep an eye on things.