My Smittybilt bumpers, swing-out spare tire carrier and flat fenders are 12 years old and flawless. No complaints — durable and heavy-duty.
I live in South Florida — every couple of months + -, I routinely hit the surfaces and crevasses with WD-40 Specialist Corrosion Inhibitor, long-lasting anti-rust spray. (in the tropics, the flat fender seams will eventually show tiny rust beginnings in spots — as long as you’re vigilant, no issues; in the Northeast and elsewhere, same-o, same-o)