How do you tell whether your RPM is to high?

To determine if your RPM (revolutions per minute) is too high, monitor your engine's performance and listen for unusual noises, such as knocking or excessive revving. Check the tachometer; if it consistently approaches the redline, it may indicate you're operating at an unsafe RPM. Additionally, if you notice a decrease in power or fuel efficiency, it could be a sign that your engine is over-revving. Always refer to your vehicle's manual for the recommended RPM range.