Real-time video sequences are common in some genres (e.g. sports, event coverage, music) but rare in fictional video such as drama, comedy, etc.
Real-time video can be a challenge, especially if you are shooting with one camera. If the scene is fairly static there should be no problem (e.g. a piano recital), but if you are trying to follow a dynamic scene while walking with one camera, you need to be on your game to make sure the footage is 100% usable.
The most common way around this problem is to use multiple cameras. Sporting events often have a dozen or more cameras from different angles, meaning the director can always use the best shot, and cameras can reposition while they are not being used.
Some music videos make a feature of using a single shot for the entire video. This can be very effective and generate a point of discussion.
A variation of true real-time video is a serialized story such as a soap drama. Although each individual episode contains time-compressed story-telling, the series as a whole develops more-or-less in real time. A year in the series takes a year in real life to watch. In this way the viewer feels like they are following the lives of the characters.
Another, slightly different example of "pseudo-real-time" is the TV series 24. Each episode is portrayed as taking place over one hour for a total of one day in a 24-episode season. A number of clever tricks are employed to create this illusion, involving a combination of time expansion and time compression. Of course the series also has to allow for commercial breaks.
Next page: Compressed time