A:Answer This is from the instructions: You should do it at least once a month.
CARING FOR YOUR TRIMMER
OILING BLADES
For best results, put one or two drops of Wahl Clipper Oil on the blades only when necessary, or approximately once a month. Motor bearings are permanently lubricated—do not attempt to oil. When oiling your trimmer, turn the trimmer “ON - I,” hold the unit with the blades facing DOWN and squeeze one or two drops of oil onto the blades. Wipe off excess oil with soft cloth.
NOTICE—DO NOT OVER OIL!
Excessive oiling or application of liquids will cause damage if allowed to seep back into motor.
BLADE CARE
Trimmer blades have precision-hardened, ground and lapped cutting teeth. Blades should be handled carefully and never bumped or used to cut dirty or abrasive material. Never rinse the blades with water, or the blades may rust. Clean with the included brush.
CLEANING/STORAGE
Before storing your trimmer, use the cleaning brush to whisk any loose hairs from the unit and the blades. For units with a soft-touch grip, use a damp cloth to wipe down the body of the trimmer, taking care not to get the blades wet. Store unit in such a manner so that blades are protected from damage.
When the trimmer is not in use, the trimmer guide/blade guard attachment should be in place to protect the blades.
This appliance should be stored in a manner where it is not subjected to Crushing, Heating above 100°C (212°F), or Incineration.
