A chain is a very reliable part of a conveying machine. You can expect very long life from a chain if you've followed the selection and operating guidelines properly.
However, it is important to inspect a chain periodically to make sure it is operating correctly. During long-term use, pins, bushings, and rollers gradually wear. An unexpected shock load or the operating environment may cause problems. To avoid any accidents caused by these factors, you must regularly inspect the items shown in Figure 7.19, and address any problems as described in Basics Section 7.2.6. Plan at least monthly inspections. If the chain is used in harsh conditions, inspect it more frequently.