Just as a skillful soccer player knows when to run with the ball and when just to hold the ball, a skillful trader should know that there is no need to always trade, and the need to know when to trade, and when to just observe the market. knowing that can also help to improve the profit they make by reducing the losses they can make by trading at wrong times.
Another time to avoid trading is during holidays.
That is a good point, traders are used to take action whenever they see something happening on the market, so eventually this becomes their default reaction to anything, but this is a mistake, there are market conditions that should not be traded and the best thing you can do is to simply go out and do something you enjoy instead of staring at your screen, however for a trader this is something very difficult to do, so they will try to trade during those difficult market conditions and lose a lot of money they could have saved themselves by literally doing nothing.