Honda Pioneer 1000 2017 Owner's Manual page 207

Refer to Safety Precautions on page 123.
Brake pad wear will depend upon the severity of usage and driving
conditions. The pads will wear faster in wet or muddy conditions.
Inspect the pads during all regular service intervals to determine the
pad wear.
Note that the pads are designed to make a metallic noise during
braking when they reach the wear limit.
If you hear a continuous metallic friction sound when applying the
brakes, the brake pads need to be replaced. Have the vehicle
checked by a dealer.