It resists rust well, but it can show surface corrosion in environments with high chlorides.

Yes. 316 stainless steel is widely recognized as the preferred marine grade because of its molybdenum.

Yes. 304 works well outdoors in non coastal environments without heavy chloride or salt exposure.

If your project is in marine or corrosive conditions, yes. The added corrosion protection often outweighs the higher cost.

The primary difference is corrosion resistance. 316 contains molybdenum, so it resists salt, chlorides, and harsh environments more than 304.