These days, most cameras and lens build quality is pretty high. Even if not completely weather sealed they can still take quite a lot of abuse from nature. Sometimes, though, you do want to take the extra step to protect your kit.
Landscape Photographer Benjamin Jaworskyj has a great tip to help cover your gear at virtually no cost. I used to use one of the more expensive solutions. It worked rather well, but it always did feel like overkill. This solution is much easier, and uses less room in your camera bag.