What do you do when your content becomes out of date? You have 3 options:
Reorganize – take existing content and restructure it in a way that is more useful to your prospects.
Rewrite – companies often find it useful to rewrite content when it is either dated or has been exhausted due to a high level of previous consumption.
Retire – every piece of content has a shelf life. You cannot use the same content indefinitely.
Source: Marketo whitepaper, Creating Content That Sells