Final answer:
Both wind vanes and anemometers experience problems with friction, which can decrease accuracy and lead to failure, necessitating regular maintenance.
Step-by-step explanation:
A problem experienced by both wind vanes and anemometers is the issue of friction. These instruments rely on moving parts to measure wind direction and speed, respectively. Over time, exposure to the elements including dust, rain, and varied temperatures can cause wear on their moving components, leading to a decrease in accuracy or even failure. Both devices must rotate or pivot to respond to wind conditions, which means that friction can impede their free movement, affecting performance. Regular maintenance and the use of high-quality materials can mitigate this issue, but it remains a fundamental challenge for accurate long-term operation of both wind vanes and anemometers.