yeast doen't really get worn out. The beer gets worn out first. Just like your car, the yeast stops when it runs out of fuel.
That is not all there is to it though. Now that the conversion to alcohol is complete the yeast will clean up after itself and remove some byproducts of the conversion process. Leave it be for at least 7 days, better yet, make it 10 or 14 days (I go 21 days) in primary and your beer will be all the better for it. You could go straight to bottle after 21 days if you wanted to. Generally I only secondary after 28 days or if I need to free up a primary for a new batch.
On Tap: 1. Kelly R. IPA, 2. Roter Hund Hefeweizen, 3. Bud Killer Blonde, 4. Red Dog Pale, 5. Roter Hund Oktoberfest, 6. Pumpkin Ale, 7. McRed's Stout (with new nitro system and stout tap,) Cream Soda, 8. ESB # 3, & 9. Ordinary Bitter.