What are the disadvantages of using a ruler?

Using a ruler can have several disadvantages, including limited flexibility for measuring curved or irregular surfaces, which may lead to inaccuracies. Additionally, rulers can be difficult to read precisely, especially if they are worn or not clearly marked. They also require a flat surface for accurate measurements, making them less effective in certain environments. Lastly, relying solely on a ruler may not account for the thickness of the marking tool, which can affect measurement accuracy.