Low-sense & High-sense gaming
You will often read about high-sense and low-sense gaming. Occasionally you even might read about mid-sense gaming, but what exactly is meant by that? Depending on your mouse settings you have to drag your mouse at different distances to accomplish movement in games. The distance you have to travel with the mouse to accomplish the same distance of movement in a game is set into three categories measured by the DPI (dots per inch), so the number of dots captured by your mouse's sensor when you move your mouse one inch. Standard mice have something between 400 and 800 DPI.
Low-sense gaming
Low sense often goes very low - often even below 500 DPI, but generally everything below 1200 is called low sense gaming. If you play as a low sense gamer, your mouse travels a very large distance. You very likely will also need a rather large mousepad to play that style. Low-Sense gamers tend to have a higher precision.
High-sense gaming
Generally speaking everything above 2400 DPI (some might even say 2800 DPI) is called high sense gaming. You will need a mouse with rather high DPI settings. I would also recommend a mousepad aimed for that playing skill as your sensor can use help to increase tracking precision. By the way the Razer DeathAdder Elite has an excellent sensor with an accuracy of 99.4% which is at present the highest value available on the market - that is the mouse I am currently using.
Mid-sense gaming
Everything in between (1200-2400) is called mid-sense gaming.