How can you quickly duplicate an object in Illustrator?

Pressing Ctrl + D (or Cmd + D on a Mac) is the most efficient way to quickly duplicate an object in Adobe Illustrator because this command not only creates a duplicate of the selected object but also allows for easy repetition of that action. When you duplicate an object using this shortcut, Illustrator automatically places the new copy directly adjacent to the original, following the last transformation applied. This is particularly useful when creating multiple copies in a specific arrangement or spacing without needing to manually adjust each one.

Other methods, such as copy and paste using Ctrl + C and Ctrl + V, involve an extra step since it requires you to paste the object after copying it. While using the Layers panel can manage and organize your objects, it's not primarily aimed at duplicating them and requires more interaction than the straightforward duplication command. Right-clicking and selecting Duplicate is not a standard option in Illustrator, making it less practical compared to the other methods.