The person doing the experiment again usually gets that benefit more efficiently if they start by learning what the people who already did the experiment thought they learned.

Which is why the education system doesn't first teach you about gravity by giving you two cannonballs and pointing you at a likely tower.

This is not to say that there aren't good reasons to have people do things again. You aquire useful skills. The knowledge sticks better. It may be entertaining. It gives an appreciation for what the research entails. And the first few times it is necessary to show that the experiment is reproducible and doesn't depend on hidden factors that the researcher didn't see.

In this case the benefits are rather one-sided. Even if he eventually writes his own clustering sytem, he will learn more if he first studies what people already know about the topic.