@masoud There's no need to free one's entire device in order to install the flexible repository of !fs that is # ;)

Most people I know have already installed F-Droid since it's simply much easier. No hassle with account registration etc. and they get all the software they need through there. (and if it's not there, they can easily receive it from a friend with the built-in app sharing functionality even if the original source is proprietary and closed!)