Would time seem different if we had more of it? Would it pass more slowly? Would we get more out of it? In Tuck Everlasting, time lasts forever (literally!) for the Tucks. And it seems like Tuck is worse for the wear because of it—he's unable to treasure the smaller moments in life because he knows they are infinite. For Winnie, on the other hand, every second counts. The twenty-four-hour adventure she has will be one of the most important days of her life, that's for sure.
The moral of Tuck Everlasting is this: it's not about how long you live, it's about what you do with your life.
Winnie is immortal, too—we're still talking about her, aren't we?