A slight disagreement, Ed.
Whole peppercorns will last two days longer than forever. It's only after they've been broken or ground that their essential oils degrade.
The entire spice trade was based on the simple fact that whole spices do not lose their potency. The spice caravans typically took two years---and often longer---to get from the spice origins to Venice, with no ill effects.
The important thing for Sunny to understand is that, for best effect, she should be buying whole spices, rather than preground, and crush or grind them just before using.