Is it beneficial to regularly read papers outside your field?
Understanding papers outside your field can be surprisingly difficult --- every field develops its own specialized terminology and shared background knowledge. A much better advice I once received from a very productive researcher was: Try to attend research seminars outside your field. These are typically more accessible than "cold" paper reads, and you have the advantage of being able to interactively ask questions. Just talking to people about their research can be extremely useful as well. You'll occasionally hear stories about how someone from field A happened to join a lunch table with people from field B and realized that he has the tools to solve their long-standing open problem (or, conversely, they have a tool to solve his).