What Is Repeat Experiments
Experiments are repeated simply to verify results. Different science disciplines have different criteria for determining what good results are. Science is built on the assumption that published experiments have repeatable and predictable.
Secondly the reason to repeat experiments is to develop skills necessary to extend established methods and develop new experiments.
Refining observations is also reason to repeat. Sometimes the experiments are repeated to study and/or improve them in way. The scientific method informs us that it is best to only make one change at a time.