I've been reading articles about slating, and it is a very crucial part of filming. Not only does it help organize the shots, it makes it so much easier for the editor to synchronize the audio and video. It will keep an accurate account of which shot is which to go along with our shot sheets, and make editing so much easier and more efficient. It's going to be difficult and time consuming for our editor (sorry Skyler...) to put everything together because we did not slate for every shot. Without the slate, he will have to do trial and error to synch the visuals with the audio. It will be a big waste of time.
A tip for everyone, in case you don't know: the best way to ensure the slate is in frame is to slate on the actor's mark with the slate at eye-level.
Another interesting tip: sometimes there are shots that using a slate before would not be advisable. For example, a shot that requires spontaneous action or a shot that may distract the actor in a very crucial moment. So what should be done in these situations? You use an end slate. Once the shot is recorded, the slate is placed upside-down (to signify an end slate) in front of the camera, the voice slate is said, the clap is made, and the director yells, "Cut!"
And here is a funny article about slating by Evan Luzi: The 10 Commandments of Slating
Another great article about what words to say when slating: Slating the Alphabet from Apple to X-Ray
Here is a behind the scenes look of the clapper/loader, Cameron Matheson, from Van Diemen's Land:
And here is a montage of all the fun slates Geraldine Brezca did on Tarantino's Inglourious Basterds: