If you find that your beer faucet feels loose or is visibly loose, it is not broken. The faucet attaches to a shank that goes through the beer tower. Under the cap on the top of that beer tower is a nut. Sometimes those work themselves loose and just need to be tightened up. Below are some images and steps that will assist with that.
Here is what a loose faucet looks like (You can see the shank threads behind the decorative collar):
1) Pop the top off of your tower. Different towers have different tops, but all of the towers we use have removable tops. They fit in pretty snug either over top of the outside of the tower or with an O-Ring on the inside of the tower. You can see a seem at the bottom of the cap where it can be removed. Be careful when removing this top to not chip it or the tower. A plastic pry tool is recommended, but for this demonstration we used a screwdriver.
2) Locate the nut for the shank under the cap. There is some foam insulation inside that you can slide out of the way if need be. Just remember to put it back in place when you are done.
3) Use a tower wrench to tighten the nut. You may have to use your other hand to line the faucet up so it is straight after tightening down the nut.The decorative collar has a crescent shaped cutout to hug tight up against the tower to assist with this alignment.
There are specific wrenches made to slide over the beer line and make this job easier. You can find these by searching "Tower Wrench" on Kegerator.com or any other beer supply site.
4) Pop the top back on and you are ready to go.