Car sales from either a motor trader or private seller must follow set procedures. A roadworthiness certificate less than 30 days old is mandatory for the seller. Be wary of offers of an extended warranty. Motor traders must give a warranty on a used car less than 10 years old with modest mileage. Cars sold by auction carry no warranty. Cancelling a car sales contract, called recission, must be done quickly. Several grounds exist for legally cancelling a contract. A cooling-off period applies to car sales. The Motor Car Traders Act 1986 (Vic) allows for cancellation of contracts if the odometer reading is wrong or if the contract lacks prescribed particulars. There are financial penalties for withdrawing from a contract.