Is Your Faucet Base Constantly Twisted? You Can Fix That
The base of your sink faucet, called the base or escutcheon, ideally should look like it's lying straight across the far end of the sink. Yet so many times the escutcheon ends up crooked, with one end closer to the sink than the other. Given that the faucet doesn't appear to be loose, the continued curving can be a mystery. But it doesn't have to be. And best of all, you can fix any crookedness you find.
Too Much Force on the Handles
If your faucet has separate hot and cold handles (and not one central handle or knob), it could be that you're turning off the faucet with too much force. Faucets that have handles usually turn off when the handle is pushed away from the user. Too much force can make an escutcheon scoot forward just a tiny bit, and over time, if one handle is favored over the other, all those tiny scoots add up. In this case, the solution is to readjust the escutcheon and ease up on the handles. You may also want to replace the faucet with one that has a central handle for both water temperatures. A plumber can do this for you if you don't feel comfortable removing and replacing the faucet assembly.
Deteriorating Gasket or Putty
Many faucets sit on a gasket that is held in place on the sink with plumber's putty or a similar type of adhesive. This adhesive has to be removable, so you can take out the faucet if you want to later on. That also means that it doesn't take much to loosen it as it gets older. As the putty or even the gasket deteriorates, it becomes easier to move the base or escutcheon. It might not feel loose -- you might not be able to rattle it -- but it moves over time as you turn on and off the faucet, and this can happen even if the faucet has knobs and not handles. You'd need to replace the gasket or putty in this case.
Poor Initial Installation
It's also possible that the initial installation of the faucet was done incorrectly. Not enough putty used, water trapped underneath, defective gaskets, and a host of other problems can prevent good installation. As with a deteriorating gasket or bad putty, you'd need to replace them to solve this situation as well.
Removing a sink faucet means messing around under the sink. You can do that easily, but if you're still not comfortable with plumbing repairs, call your local plumbing services. This is a simple job that won't take long at all.