[Doggie 1]

No checks here in WA either.
Same as above, if a car is re-registered after having come from interstate then it is checked, or if a car receives a defect notice from the police it is fully checked.
But failing that, it is possible to buy a car today, keep it and not have it checked for roadworthiness for the next thirty years.
Having said that, the police do a pretty good job of putting unroadworthy cars off the road though.