If you're tinkering with Vim's config, did you know you can easily reload the settings file without restarting Vim? You basically just need to "source" the settings file:
:source ~/.vimrc. You can use the abbreviated command, so it's just
:so ~/.vimrc. If you use a plugin manager like Vundle and keep the list of plugins in
~/.vimrc, then you'll need to source it after changing the list of installed plugins. There's no need to quit and restart!
Once you get the hang of this, you'll find you just open vimrc during editing sessions, without opening a new terminal and a fresh Vim to edit something.
Update: Piotr S. wrote in to say you can make Vim automatically write your settings file by using
autocmd bufwritepost .vimrc source $MYVIMRC.