My site gets crawled very frequently... Yet I have one article mysite.com/tv-set-reviews, changed the URL to mysite.com/tv-reviews and 301'd the new URL to the old one and it's STILL not realizing it's been 301'd almost 3 months later. It's absolutely ridiculous. Now the article can't rank well because it thinks it's dupe content and both articles are in the search engine still. Same problem on another site.