TLDR; You should start using moustache wax either when the hair begins to overgrow your top lip, or when your moustache is about a centimetre in length and long enough to style.
Moustache wax is used primarily for its ability to hold facial hair in place. This is done by heating up the wax, applying it evenly throughout the moustache, teasing the hair into position and allowing the wax to cool down and strengthen.
The history of moustache is, of course, a history of a men's hair trends, fads, fashions and, perhaps more peculiarly, tax laws.
Over the last week, I have set out to compile a list of the most important moments in the history of the moustache. After all, if we don't learn from the history of the moustache, we're doomed to repeat the history of the moustache.