Of course as an inexperienced developer, I could be wrong and his way might be better so my question is what ways can I do to better judge if a senior developer advice is a good or bad/outdated one.

You can become an experienced developer. Until you do that, you'll be ill-equipped to judge whether or not your intuition as a junior was right, and by then it won't matter.

In the mean time, read Joel Etherton's answer.