This is one of my bosses favorite sayings. I must admit its pretty good and for sure its something you need to do. Its especially something you need to do if you when you walk into a new environment and the previous care taker is no longer available.
Check your backup policies, make sure that you aren’t backing up 15 rotating daily copies of a version controlled repository to tape every day (all 15). Check your storage systems. Make sure that the raid levels are sane, and that redundancy and hot spares are available for all raid sets unless its meant to be some fast scratch disk.