[thomastjeffery]

Does reading make you a better writer? Yes.

What does it mean to be a good developer? Do you simply want to write your own black-box undocumented software? Then there is a much lesser advantage to reading other projects' code. On the other hand, if you want to manipulate another codebase, or use another library, reading code is a necessity.

That leaves one final question: Is it beneficial to your own development skill to read others' code? Yes. Proficiently reading others' code is a very beneficial skill, even if you do not intend to write code to be read by someone else. Not only will you get better at reading your own code, you will learn idioms and practices that will improve your comprehension, and writing skill.