The answer to this question varies from project to project and depends on what it is you’re trying to convey with your image. That said, we believe that you should use the fewest images possible while still showing what you want to show.
Think of the lenticular as a pie.
Each frame is a slice of the pie. The more frames you use, the smaller each slice will be. This means that each frame will be less clearly viewed and will “ghost” with the frame before and after it. This isn’t so bad if you’re trying to show a baseball swing. But if you’re trying to display images that are very distinct from each other (more like a slide show), the slices (i.e. frames) need to be more distinct. Short answer: The right number of frames to use is usually somewhere between 2 and 12.