The criteria on issues like this should always be: Are answers to this question likely to help other people in the future?
If an answer is so localised that it will never be of use to anyone else, then it should be closed as such.
If it is so general that it fits within the remit of Superuser or one of the operating system specific sites (as, I believe, with the R package installation question), then it should be migrated there. If we can't migrate the question for some reason, it should be closed with a suggestion that the other place is more appropriate.
It is the grey area in-between that we should consider appropriate for
That might include questions where the documentation for a package used by a Computational Scientist is insufficient to complete installation, or makes assumptions about the knowledge of the installer that is inappropriate.
For instance, I recently went through the effort of installing wxMaxima from source, and the documentation doesn't actually tell you (when) to install Maxima, it just assumed that it is already installed and working in the default location. Similarly when I came to install Maxima from source, I discovered several essential links were broken, which meant that I had to make several leaps of faith to get it to work.
Other questions which might still be appropriate include those to do with configuring the software optimally for use cases outside of the main purpose of the software.
Obviously there are caveats. The Questioner should show what they have done to try to get the software installed. They should explain how that failed and what else they tried beyond the documentation.
Ultimately though, many of the packages we use are complex and often highly configurable. Setting up those packages in an optimal way is often beyond the scope of standard documentation. These sorts of questions thus have the potential to be very useful to the