Question

Why do scientists try to repeat other scientists’ experiments?

Answer 1

Scientists repeat experiments for reliability.  Experiments have to be repeated, since performing an experiment only once, does not prove a scientists theory on the experiment, which they develop by performing the experiment.  And then performing the experiment again or even many times to prove or disapprove their theories.  Btw, before an experiment begins, the scientist will make a hypothesis of what they believe will happen.  If proven correctly, they would then use those results they record throughout the experiment, from beginning to end to prove whether or not their hypothesis are correct or incorrect. 

Answer 2

So that they can prove the other scientists views wrong and develop a new theory in which there is more sense and credibility.