The frequency with which you need to replace a surf leash will depend on several factors, including the quality of the leash, how often you surf, and the conditions you surf in. In general, a high-quality surf leash should last for several seasons if it is well-maintained and not subjected to excessive wear and tear
However, it is always a good idea to regularly inspect your surf leash for signs of damage, such as fraying or cracking in the cord, or a worn or damaged cuff. If you notice any of these issues, it is best to replace your leash as soon as possible to ensure your safety while surfing.
On a similar note, if you have an older leash that has been subjected to frequent use and exposure to saltwater and sunlight, it may be a good idea to replace it even if it appears to be in good condition, as the materials may have weakened over time