Q:

apt-get autoremove dangerous?

I was compiling a tool called Rejoystick so I installed a few packages and dependencies. But now I don't need it any more so I removed those packages. Running apt-get shows that I have some packages that are automatically installed and are no longer needed. 
But I have a bad experience with apt-get autoremove. It broke my desktop environment when I uninstalled wine some time ago. Luckily, I had a clonezilla partition backup then, but this time, I don't have a backup. So I'm cautious. Running apt-get shows these packages are orphaned 
  gir1.2-gtk-2.0 libasound2-dev libavahi-client-dev libavahi-common-dev
  libcaca-dev libcairo-script-interpreter2 libdbus-1-dev libdrm-dev
  libexpat1-dev libfontconfig1-dev libfreetype6-dev libgl1-mesa-dev
  libglu1-mesa-dev libharfbuzz-dev libharfbuzz-gobject0 libice-dev
  libpcre3-dev libpcrecpp0 libpixman-1-dev libpng12-dev libpthread-stubs0-dev
  libslang2-dev libsm-dev libx11-dev libx11-doc libx11-xcb-dev libxau-dev
  libxcb-dri2-0-dev libxcb-dri3-dev libxcb-glx0-dev libxcb-present-dev
  libxcb-randr0-dev libxcb-render0-dev libxcb-shape0-dev libxcb-shm0-dev
  libxcb-sync-dev libxcb-xfixes0-dev libxcb1-dev libxcomposite-dev
  libxcursor-dev libxdamage-dev libxdmcp-dev libxext-dev libxfixes-dev
  libxft-dev libxi-dev libxinerama-dev libxrandr-dev libxrender-dev
  libxshmfence-dev libxxf86vm-dev mesa-common-dev x11proto-composite-dev
  x11proto-core-dev x11proto-damage-dev x11proto-dri2-dev x11proto-fixes-dev
  x11proto-gl-dev x11proto-input-dev x11proto-kb-dev x11proto-randr-dev
  x11proto-record-dev x11proto-render-dev x11proto-xext-dev
  x11proto-xf86vidmode-dev x11proto-xinerama-dev xorg-sgml-doctools xtrans-dev
  zlib1g-dev

I'm not sure if I should run apt-get autoremove. I was searching details related to each of these packages so that I can understand which ones are needed but they all seem important e.g.

gir1.2-gtk-2.0 

I have Cinnamon, GNOME and Unity installed, I think apt-get autoremove will break something. Any help will be appreciated. 
Thanks for reading.

A:

As others mentioned, autoremove should be safe, but then again, you said that you have bad experiences, and I also remember autoremove removing some stuff that should not be removed.
It seems like autoremove can have problems with some meta-packages. Say you installed the gnome meta-package for the entire gnome-desktop (or it was installed when setting up the system), which also includes programs like evolution and lots of games, which you might want to remove, because you are using thunderbird and do not want to have those games and the like. This requires you to also remove the gnome meta-package, since it depends on all those packages. But this will make all the other packages that were installed as dependencies of gnome "auto-removeable", including e.g. gnome-shell, which you most likely want to keep if you want to continue using that desktop.
So it's always a good idea to check the packages recommended for auto-removal. If you are using a graphical package manager like synaptic, you can easily do so and uncheck the "automatically installed" flag from packages you want to keep (like gnome-shell in the above example). This will also remove all the packages those depend on from the auto-removeable list, so you might only have to "fix" a few of those, and not all.
Still, it should not remove anything that's really essential to your system, so even if you accidentally removed e.g. your desktop, you can still boot and log into your system and revert those changes using the command line.

A:

It should be perfectly safe to run sudo apt-get autoremove This should only remove packages that are not in use or needed any longer.  If its a necessary package that would "break" your system if removed  it shouldn't remove it.

