Choosing the least powerful tool suitable for a given purpose.
The least power principle or least power rule is meant to prevent security flaws and improve work flows.
It has close relations with the principle of least privilege and the single responsibility principle.
Let's say you want to edit a text file quickly.
Yes, you could open word, scroll with your mouse down to page 3 and den make the 1 character change.
Or you could use a tool like Vim from the command line and be done with the change faster than word even finished booting.
Choosing the least powerful tool for a task is often the fastest way to accomplish a given goal.
In your daily life, not using an account with administrative access on your computer is advisable.
All you need to do is use software, not installing software.
If you then accidentally download a malicious software from a link, the damage that this software can cause is severely limited, since the active account lacks the necessary rights.
Choosing the least powerful tool for a task often prevents security problems before they can arise.