The refresh rate of a monitor is important as it refers to the number of times per second a monitor can update.
The most common monitor refresh rate for a monitor is 60 Hz which means that they refresh the entire screen 60 times per second.
In the last few years, manufacturers have begun marketing panels with more than double the refresh rate of a standard LCD panel pushing the refresh rate to 120Hz and even 144Hz. A high refresh rate promises smoother scrolling and less blur in games.