thing is beams and shafts etc will rust becuase they are what takes thehit from stones etc more than the floor does

but if everythigng is done correct then it should last longer than a year but it all depends if its driven in all weathers, if it is then winter time it needs cleaning a lot more regular

maybe a coat of something like wd40 to help protect it from water etc, so once its washed spray on yes it will get dirty but at least you know with a simple wash it will stillcome up like new again

its worth just doing it fully once and doing it rite as id imagine you know,then its just down to general maintenance and a clean ad keeping ontop of it, as if its not kept it will just go back to how it was