One of the first questions a photographer that is entering the wedding field will have is what equipment is needed in order to cover the day in full. That is a very good question and an arbitrary one at that. I am going to do my best to name some of the equipment that I find to be most useful. I will also try and name some equipment that is helpful, but not a necessity. Let's get started!
The first item that you need is obviously a camera. And not only one camera, but two cameras. Murphy is walking around and looking for his next victim and you do not want to have to explain to your clients why you cannot continue to cover their "once-in-a-lifetime" event. If you do not have two cameras, no problem. You can rent good quality cameras online for a very reasonable price. There is no reason that you should not have a backup camera. My suggestion is to get a camera exactly like the one you have and set all of the settings the same so that you will be able to work seamlessly. Another advantage to having an extra camera is that you will be able to equip it with another lens and have it handy for fast shooting.