Milo receives an important gift in nearly every landmark he hits on his journey through the Lands Beyond. If you've ever read another quest story, you know that this isn't unusual. Everywhere a traveler stops, he's likely to get a gift – whether in the form of an object or just some much needed advice – from the residents of that place.
For Milo, each of the gifts he receives will turn out to be important when he gets to the most dangerous part of his journey: crossing the Mountains of Ignorance to reach the Castle in the Air.
Let's take a closer look at the gifts themselves:
From King Azaz, Milo gets a "box [with] all the words [the king] know[s]" (8.64).
From Alex Bing, he gets a telescope that shows "things as they really are, not just as they seem to be" (11.25).
From the Soundkeeper, he gets a collection of little noises
From the Mathemagician he gets a pencil, his "own magic staff" (16.70).
And sure enough, each of these gifts helps Milo save himself and his friends from a terrible demon. The telescope reveals the demon of insincerity as someone who's not dangerous at all; the magic staff unmasks the Terrible Trivium's plan; the words scare the giant so much he lets the travelers go; and the sounds dispel the fantasies set up by the Senses Taker.
So what's the big deal? It's just a bunch of objects. Or is it? If you think about it, every time Milo uses one of these gifts, it feels like the people Milo met earlier on his journey are coming back to help him on his quest. It reminds Milo of the rest of his journey and reminds us, as readers, just how far he's come.
One more thing: Have you ever heard the saying about a starving man and fish? It goes something like this: Give a man a fish and he eats for a day; teach him to fish and he eats for a lifetime. Translation: if you give a guy a fish to eat, he'll have food for one day (not bad). But if you can just teach him how to fish, he'll be able to feed himself forever (much better).
Both King Azaz and the Mathemagician teach Milo how to fish, rather than just giving him those fish to eat. What we mean is, they give him tools that he can use to make the learning process his own. It turns out learning is a process of discovery, not just a set of right and wrong answers to recite from memory. Lesson learned!