I don't think there is a definitive answer to this, but worth the discussion: How to handle an expired ad in a classified / auction site? Michael Gray mentioned you should 301 it to it's category page, and I'm inclined to agree with him. But some analysts say you should return a "product/ad expired" page with a 404. For the user I think the 404 aproach is best, but from a SEO perspective that means I'm throwing link juice out. What if I 301 him from the ad, and show a message saying why they're seeing the listing page instead of the product page? Thoughts?