Every 100 Uses
The crossbar rail is upside-down, directly exposed to fumes from the nozzle and heat, which can dry out the lubricant and leave a thin layer of particulates. Run your finger over the surface of the rail. If you take off a layer of debris, clean the rail with a lint-free cloth, apply a dab of machine oil on each end, and run it back and forth its length of travel.
Every 500 Uses
Check the shim below the Z axis coupler on each Z motor. Replace them if they have worn thin. Otherwise, hit them with a light dab of machine oil.
Check the Z leadscrews for debris. Clean them with alcohol and then reapply a coating of white lithium grease.
X and Y Axis Rails
If these rails show signs of accumulated dust, clean the rail with a lint-free cloth. Then apply a light dab of machine oil on both grooves on each of the carriage, and run it back and forth its length of travel.
Remote Elastic Lock
Check the lock for signs of wear. Ensure that neither the wire cinching screws nor the Fixed Pulley Hub set screw have come loose. Retighten if necessary.