More than one button in the same pin
Why waste multiple analog pins for two switches each, when you could do any number of buttons on a single analog pin?

Two ways of doing it. One is in series, the other is parallel.





This is how some car steering wheel audio controls are. And how some of the older ipod inline controllers work.

Depending on the resistors you use, if you need multiple buttons pressed at the same time, and how sensitive your analog in is, you could have all 10 buttons on a single pin.