To sort of quote 14th Century Franciscan Friar William of Ockham (or rather the beginning of his Wikipedia page):
"Occam's razor (or Ockham's razor) is a principle from philosophy. Suppose there exist two explanations for an occurrence. In this case the one that requires the least speculation is usually better. Another way of saying it is that the more assumptions you have to make, the more unlikely an explanation. Occam's razor applies especially in the philosophy of science, but also more generally."
I find myself sometimes using this principle in my real-life job.