In some lines of work, KEEPING AN EAR TO THE GROUND is of utmost importance. For instance, a dealer in stocks and shares must know what is happening in the markets before it makes the 8 o’clock news. The trader must always have an ear to the ground and obtain information which can help him/her make wise investment decisions. Likewise someone who works in the smartphone industry. An essential part of the job is trying to discover what new developments a rival company will be coming out with.
As you have noticed, it’s possible to say either keep or have an ear to the ground.
Use the language
How important is it to keep an ear to the ground in your profession and why?