I like to tell a story (especially to my newer players) about a lesson that I learned from my father when I first started to swing a club...
I was only about 8 years old and we would often go to the public practice range together. Golf balls were sold by the basket (i.e. limited in number), so he would direct me to an area where there was longer rough, away from the hitting area and tell me to make a few dozen swings - or as many as it took - brushing the grass until it was evident that my clubhead had bottomed out in the same spot over and over. Until I could prove that I knew where my club was hitting the ground (and hitting the ground in the same place every time) I simply wasn't ready to hit a ball. So off I'd go making swings wildly until I indeed, had made a trough. He would say, "OK, you're ready."
I was lucky to have someone watching out for me at an important time. All too often I see people hitting ball after ball not knowing where their club ought to make contact. The reason this drill is so important is because good, solid contact with the ball means hitting it in the middle of the clubface. The only way to hit the middle of the clubface is to allow the bottom of the club to hit the ground.
So before you keep machine gun hitting ball after ball because they are limitless, and there are no consequences on the practice tee, make sure you rehearse the swing and take note of where you bottom out.