Certainly, a quick visual inspection of your spotting equipment should be done before every use. Are the ropes frayed? Are the swivel clips bent or broken? Does the spotting belt have any loose stitching? Is the rope running smoothly through the pulleys? etc. etc.
But the real answer depends on many factors including:
- How often is the spotting rig used?
- How big are the kids being spotted? (College age? High School? Age Group? Lessons?)
- How often is the spotting rig "shock-loaded"?
- How old are the ropes? The Pulleys? The Clips?
- What is the environment where the spotting rig is used? (Indoor? Outdoor? Near the ocean? Heavy chlorine environment? Direct sun?)
- How experienced is the person doing the spotting? (Very experienced? Novice?)
It is my suggestion that the coach or facility maintenance staff should closely inspect the entire spotting rig including the ropes, the pulleys, the swivel clips, the links that attach the pulleys to the spotting rig or the ceiling clamps, the rig itself or the ceiling attachment clamps at least twice per year -- more if the spotting equipment is used daily.
It is always best to err on the side of caution -- when in doubt or if not sure -- replace.
NOTE: Make sure the components you use are RESCUE RATED and designed and intended to be used for overhead lifting of human weight -- not the cheap imported rope and hardware sold at Big Box stores. Remember that Good Spotting Equipment is NOT Cheap and Cheap Spotting Equipment is NOT Good!