Recently I started my first job as a junior developer and I have a more senior developer in charge of mentoring me in this small company. However, there are several times when he would give me advice on things that I just couldn't agree with (it goes against what I learned in several good books on the topic written by the experts, questions I asked on some Q&A sites also agree with me) and given our busy schedule, we probably have no time for long debates.

So far I have been trying to avoid the issue by listening to him, raising a counter point, he raises his original point again (most of the time he will say best practice, more maintainable but just didn't go further), I take a note (since he didn't raise a new point to counter my counter-point), think about it at home, but didn't make any changes (I'm still not convinced). But recently he approached me yet again, saw my code and asked me why haven't I changed it to his suggestion. This is the 3rd time in 2--3 weeks.

As a junior developer, I know that I should respect him, but at the same time I just can't agree with some of his advice (I don't like his programming style too but that another issue). Yet being pressured to make changes that I think will make the project worse. Of course as an inexperienced developer, I could be wrong and his way might be better.

My question is: what can I do to better judge if a senior developer's advice is good or bad/outdated? And if it is bad, what tactics can I do to not implement it his way despite his 'pressures' and to convince my boss who is more likely to trust him?