Reading a portion of a thread I came across it being mentioned that cheaper cigars being talked about needed to be rested a few months to become fairly good. Why is this, and what exactly is it as I assume it's just that, allowing it to sit in a humidor to age a bit.

I've also seen aged cigars (up to 12 years?). If properly stored (~68/68*?) do cigars last a very long time?

I usually begin puffing on something about as soon as I get them, or within a week. The last few will have certainly sat a bit.