In what cases does the first basemen hold on the runner?

My son just began to play firstbase. I'm interested in being able to better explain to him the various aspects of the game in order that he might better understand and in turn perform better.In what cases does the first basemen hold on the runner?
If the score is close hold the runner on.


If the game is a wipeout, play behind the runner


If the runner is fast, hold him on.


If the runner is slow, play behind the runner


If the batter is lefthanded and the first baseman is holding a running on be sure the 2nd baseman can slide over to take some of the whole through the infield.In what cases does the first basemen hold on the runner?
I play 1st base in 2 baseball leagues.





You should always hold on the runner.





Except on a 3-2 count.





I pretty sure