Jewelers charge too much nowadays to adjust your watchband.  Moreover, if you adjust it yourself, you can try different sizings, move one link to the other side, etc. until you get it exactly how you want it.  Standing at the jewelry counter, however, you're reluctant to tell them to try it another way, and worse yet, to tell them to put it back like it was the first time.  This inexpensive tool lets you take out the little pins in the watchband without slicing your finger open with a steak knife, or whatever you were going to try.  Adjusting a watchband without this tool is like trying to put a screw in without a screwdriver.