Addicted to data - Computerworld:

"Unlike oil, the problem [with data] isn't a shrinking supply -- quite the opposite. We are smothering in its abundance. Data storage continues double-digit growth rates, and while per-unit costs continue to fall, our appetite outpaces the decline. Even more significant are the ongoing multiyear costs to manage, support and protect the data that consumes this storage."

Data expiration needs to be considered at the time of data generation - this is a discipline which is never going to be easy to enforce - when you combine legal requirements (like SabOx) with most people's desire to never throw something away that might again be useful, you end up with stuff seeming to hang around for ever.

Most organisations tend to take a manual 'spring clean' type approach - realise that things are a mess, that there's too much junk lying around, then start on a big manual process that exposes the business to large amounts of risk (that something vital be lost) and time spent on the project.