As usual "it depends". Basically rust is the problem, so if you are scrupulous on upkeep (read, spend money) it will last much longer than if not. How long i

As usual "it depends". Basically rust is the problem, so if you are scrupulous on upkeep (read, spend money) it will last much longer than if not. How long is also enviroment dependents (temperature swings, salt air, emiisions etc. can make it worse)