In general, the lifespan of a pickleball paddle depends on how often it is used. Due to this, if they are used frequently, for instance in training or in a tournament, they may not last as long as a paddle that is used infrequently.
Professional players should be able to use a graphite or composite paddle for about a year before degrading. When you take proper care of them, whether you are a beginner or a recreational player, they should last several years.
You'll get more use out of wood paddles compared to composite or graphite paddles.