Brake pad wear depends on the intensity of braking, how you drive your motorcycle, and road conditions. (Typically, pads wear out faster on wet and muddy roads.) Check the condition of the brake pads at every periodic maintenance (see here).
Front brake
Always check each pad on both the right and left brake calipers.
Check by grooves (1) wear on each brake pad. If the wear level of any of the pads is equal to the depth of the groove, replace both brake pads as a set. Contact your authorized Honda dealer to perform this operation.
The illustration shows the right side, the left looks similar.
(1) Grooves
Rear brake
Check by grooves (2) wear on each brake pad. If the wear level of any of the pads is equal to the depth of the groove, replace both brake pads as a set. Contact your authorized Honda dealer to perform this operation.
(2) Grooves