The 'description' of the car should tell you if it's Registered or not...perhaps it will say "6 months rego upon sale" which means the current owner is going to pay for a period of "Registration"...generally, cars need a "Roadworthy Certificate" in Australia to be sold (and registered or reregistered) and advertisements for anything 'otherwise' should state "No Roadworthy" or something like that. If you're talking about 'photographs' of cars without number plates, it could just be for privacy reasons...car dealers etc will show photographs of cars with the plates "removed" or 'blacked out' simply for privacy. No the 'plates' don't necessarily stay with the car for the life of the car...in fact, for a fee (I think about $25) you can have plates 'reissued'...if they are personalized it is just a copy of the existing plate...otherwise you will get 'new' registration plates which will be a new "number/letter" combination.Hi all I've seen cars for sale with no number plates is it like America where you have the same registration no matter what car you have??? Also what's rego is it like car tax???