Can't speak for all brands, but most new auto manufacturers state that they prefer you NOT doing any additional rustproofing.....
on my last 16 year old Japanese sedan which I sold earlier this year, it only had the dealer applied 'rustproofing' from when I bought it in 1998 cos it was the cool thing to do, never touched it since, and not a speck of rust when I sold it.
On my last 2 vehicle purchases, i decided I would be a guinea pig and skipped the rustproofing totally.....
on my last 16 year old Japanese sedan which I sold earlier this year, it only had the dealer applied 'rustproofing' from when I bought it in 1998 cos it was the cool thing to do, never touched it since, and not a speck of rust when I sold it.
On my last 2 vehicle purchases, i decided I would be a guinea pig and skipped the rustproofing totally.....