Back in Jesus' time, teachers were probably not all that common. At least, not religious teachers.
To be a Jewish rabbi, you had to be pretty learned. Pastors are a dime a dozen nowadays. Back then, if you chose one teacher over another, by choosing one when the two conflicted, you were doubtless taking a serious side.
Nowadays, with "teachers" in every shade of gray there is...well, how do you know what teacher to pick? When everyone tries to justify their teachings from the Bible, how do you know which interpretation is true?
Some day, does it matter? Of course it matters. What you think is good and true, will affect your behavior and what sins you do or don't commit.
With a fairly continuous spectrum of teachers' interpretations and opinions, how can you tell if you're choosing just to make your life easier, or choosing what is true? How do you know that you're choosing someone who is false and just reinforcing what you wish were true, rather than teaching what is true?
After all, in order to recognize truth, you must know truth, right?
So what does the seeker after truth do?