Tools should be replaced at the first sign of edge deterioration, to prevent further damage to toolholders.
It should be fed slowly enough so that it is not under significant strain or too slow to be subject to burning.
Do not use adaptor bushings to reduce the size of the collect.
The correct router must be used for its intended purpose or it may wear out
Router mechanism must also be checked regularly
Inspect tools for collet marks which indicates slipping or dust build up. Check collet for wear.