If it is truly no longer relevant then no harm in zapping it. Consider replying with a Status: 410 Gone for search engines and give a friendly page saying "Thi

If it is truly no longer relevant then no harm in zapping it. Consider replying with a Status: 410 Gone for search engines and give a friendly page saying "This page has been intentionally deprecated due to lack of relevance" or something along that line. You can create a webmaster account on google and have it crawl your site again to purge the 410 content from the index.