As you see in a lot of the examples earlier in this book, you don't have to do a thing to your standard Timeline, organization-wise. You can let Flash play your animation sequentially, from Frame 1 right through to Frame 500 (or whatever number your last frame is) with no problems.
But you can designate certain sections of your Timeline as named scenes—or even just label certain frames—and speeding up development time, as well as make your animations more flexible and interactive.
Organizing your animation as a series of scenes speeds up development time. If you break an animation into scenes, then you can find what you're looking for quickly; you can also easily rearrange your animation. For example, say you create an animation containing a couple hundred frames (not an uncommon length). You might find yourself getting pretty tired of looking for that single eight-frame span that shows your cartoon character reacting to the marketing copy you're adding in as an audio voice-over. Your marketing team changes its mind on the copy, and suddenly your character has to smile. They change their minds again, and instead of smiling, your character now has to look thoughtful.
If you don't organize your animation into scenes, you have to slog through your animation frame by frame—all 200 of them—to find the specific images you want. But if you do organize your animation into scenes, all you have to do is zip to the scene you named ralph_reacts. And if you need to reposition ...