They are intended for use in all kinds of conditions, but they are also meant to be cared for. Like horses, you don't ride them hard and put them away wet.
Try not to let water stand on it overnight and keep a bit of oil or grease on all the steel bits. There are some bolts and other nubbins that will show some surface rust, that's only avoided by using stainless or titanium hardware. Some things we live with until it's time to upgrade something.
The 3M Scotchbrite pads are much better than steel wool for removing rust.