Proper lubrication is essential for the performance of plain linear bearings, as explained by Dave Humblet, Senior Application Engineer at PBC Linear. He compares traditional linear ball bearings with self-lubricating plain bearings made from polymers like Frelon®. The overview covers when and how to lubricate Simplicity bearings, the compatibility of various lubricants, and the science of tribology. Additionally, the video demonstrates optional lubrication systems, such as felt wicks and zerk fittings, to ensure long-term performance and minimal wear.