Why do people vote early? Unless there is an actual reason, like having something on that would get n the way of voting on the day?

It seems a bit like opening presents before Christmas or youur birthday. And after all something might happen that makes you change your mind - and in the case of the U S elections, though all the stuff in the papers is about Clinton and Trump, where there's not much room for changing minds, they vote about all kinds of other stuff, sch as numerous other political jobs, or whether to legalise marijuana.