If they appear damaged or deteriorated, replace them.

Balancer Adjustment
Torque LimiterBrake Pad Wear Inspection
Remove the brake pads (see Front/Rear Brake Pad Removal
in the Brakes chapter).
Check the lining thickness [A] of the pads in each caliper.
If the lining thickness of either pad is less than the service
limit [B], replace both pads in the caliper as a set.
Front Brake Pad [C]
Rea ...
Liquid Gasket, Non-permanent Locking Agent
For applications that require Liquid Gasket or a
Non-permanent Locking Agent, clean the surfaces so
that no oil residue remains before applying liquid gasket or
non-permanent locking agent. Do not apply them excessively.
Excessive application can clog oil passages and
cause serious damage.
...
Rear Sprocket Removal
Remove the rear wheel (see Rear Wheel Removal in the
Wheels/Tires chapter).
NOTICE
Do not lay the wheel on the ground with the disc
facing down. This can damage or warp the disc.
Place blocks under the wheel so that the disc does
not touch the ground.
Remove:
Rear Sprocket Nu ...