A short look into the Debian release schedule https://wiki.debian.org/DebianReleases provides helpful information for the endusers. In general, each version is maintained for 2 and a half year which means, the user has to install the Operating system once and can use it very long. If the 2.5 years are over the user can update to the next release with a simple command line. This brings the user in a very comfortable situation.
What is not answered in the release chart is how to program all the software. The Linux operating system contains of hundreds of programs and it's unclear how these programs are working together. From the users perspective this is a mnor problem, but it's up to the developer to program and test the code.
Perhaps this is the most obvious difference between Debian and other operating systems like Arch Linux. In Debian there are two conflicting social roles: normal users vs. developers. The social role of the user is installing the software and then it is using all the code without doing anything in return. While the social role of a programmer has to do with fixing issues, compiling sourcecode and monitor security issues.
The simple explanation is, that two conflicting roles are equal to a professional Linux distribution. If a linux distribution has only one role which is the developer, it can't be called a serious distribution. A wrong assumption is, that the conflicting roles are only available in closed source ecosystem in which the user has to pay 100 US$ for the operating system while the other side takes the money and programs the code. The surprising situation is, that the same social roles can be imited in the Open Source world as well. The idfference is, that Debian users aren't paying money. The result ist, that the quality of the software is lower. The latest Debian 10 software has a weaker quality than the latest Windows 10 version. In Windows 10 the graphics card is working better, the PC needs less energy and the installation works more smooth. These disadvantages have to be accepted by the Debian users because they get the .iso file for free.
The advantage of Debian over other LInux distributions like Gentoo, OpenSuse and Fedora is, that in Debian it's possible to become a normal end user. An end user is somebody who doesn't write sourcecode nor he fills out bug reports, but he is using the software. Very simlialr what most users are doing with Wikipedia. They type in the adress into the URL bar and read the content which was written by other.
Most Debian experts are arguing that their operating system has a greater stability than other linux distributions. What are they talking about? A naive assumption is, that stable means, that the software is secure or has no bugs. This is only partly true. The current Debian 10 stable has a lot of security issues, and some minor bugs too. What stable means more concrete is, that the development is done in a stable branch. That means, Debian contains of a unstable branch and a stable branch. The existence of a stable branch allows to publish longterm versions which are running 2.5 years on the computer. In contrast, Linux distribution which are not stable like Arch Linux or Fedora need to be updated once a week and in case of doubt, the system won't boot after the update.
The term stable is referencing to a publishing schedule in which every 2.5 years a new release is available and during this period the user is running the same version on the computer. The stable branch is a technique to provide this release schedule.