There is no right answer to how long your YouTube video should be. Some suggest that a YouTube video should be at least 30 seconds and around 7 to 15 minutes for people to watch for as long as possible.
However, the video should be no shorter or longer than it needs to be. Depending on what your video content is about, it should include only the necessary information that engages your viewers and entertains them long enough to watch the video up until the end.