"For all the efficiency and continued evolution of Debian's APT tools, some gaps in package management functionality remain. One of the largest ones is that, when a package is removed, any other packages that depend on it are not removed. The result is a growing number of orphans on the system--that is, packages that serve no purpose for the system as a whole, although in some cases they continue to be useful individually. Similarly, while you can keep track of security announcements for Debian or distributions derived from it, the basic package system has no way of telling you which vulnerabilities might affect your system. To compensate for these lacks, you can turn to a group of housekeeping tools that make maintaining your Debian system easier and more efficient.
"As experienced users might expect, you need to have some sense of the Debian package and repository systems to make full--and safe user of these packages..."
