Well, the type of bean plays a significant role in whether or not to let rest. It is more of an art in this respect. You have to taste, and taste, and then taste some more. The best way to learn is to try it. Roast some coffee, taste some right away, let some rest for one day-taste it, and then try the remainder on the third day. Take notes while doing this and you will discover quite a bit.
I don't think there is a solid rule for which coffee should be rested, although I see the deeper roasted coffee accepting a rest better.
And yes, use an airtight container for the resting.
Hope this helps.