Debian comes with three flavours: stable, testing and unstable. Stable is rock solid, it never breaks, and is never updated; unstable is updated often, breaks often, and is fixed often. Testing is between the extremes. Stable contains packages which are years old, and is often said as outdated, lacking recent features. There is a new version of Debian every 2 or 3 years, by the time of release, the package contained in previous version are already 4 to 5 years old.
Some distributions are publishing new releases every half year and claims they are stable enough for everyday use. Is that true? Let me take an example. Ubuntu gets a new version in each April and October, after a month of beta testing. The distributor claims that it is stable enough after a month of beta testing but people say that even Debian unstable is more stable than Ubuntu stable releases. How can Ubuntu be trusted for use on a 24/7 server? LTS? Only 1.5 months beta testing. Debian? New package -> unstable -> no RC bugs filed in 10 days -> testing -> whole testing frozen for a long time (about 6 months) -> rock stable (and outdated).
Therefore, stable comes with a price: outdated and nearly-forgotten very old versions of software.