A new Emacs version was declared stable yesterday, the last major revision was released in 2012 so it's quite the occasion.
A few years ago I've started building it from source instead to depend on binary packages, mostly because I couldn't find a recent version on the Debian repositories. All things considered the process was less tedious than I feared.
The following is more of a personal note on what I need to remember the next time I decide do install a new version or minor release, but it can convince the reader that is not so scary.
To ensure I have a suitable build environment, I install the "dev" dependencies reported in the Debian packages, usually this is enough unless a new feature is integrated, for example the new release has support for Cairo drawing or Xwidgets. For sure all the required info can be found in the release notes. Once downloaded the sources and applied eventual patches, it's the usual configure; make; make install if extracted from a tar archive, autogen.sh should be required only when pulling directly from the git repository:
$ ./autogen.sh
$ ./configure --prefix=/opt/emacs25.1
$ make
$ sudo make install
Now the install part of the makefile should ask to set movemail as setuid root; I don't use Emacs to read email, but I usually run the command when prompted.
The last thing I do is creating a symbolic link for emacs and emacsclient in /usr/local/bin and checking that the path in my emacs.desktop and emacsclient.desktop files in ~/.local/share/applications are pointing to the correct executable.
Done.