It is important to have a variety of back-up reinforcers on a reinforcer menu or to change them up on a regular basis because:

Having a variety of back-up reinforcers on a reinforcer menu or changing them regularly is crucial because it prevents monotony and keeps individuals engaged in the reinforcement process. If individuals are presented with the same rewards repeatedly, they may become bored and lose interest in working toward the tokens or behaviors needed to earn those reinforcers. This boredom can diminish motivation and lead to a decrease in the desired behaviors that the reinforcement system is intended to encourage.

When reinforcement is effective, it ideally maintains the individual's interest and encourages continued participation in learning or behavior modification. By regularly updating the reinforcer menu, an environment of novelty is created, which helps sustain motivation and interest over time. This principle is foundational in behavior analysis because it underscores the important role that variability and unpredictability play in a successful reinforcement strategy.