Less chatter, more gold.

I am always asked what level of sensitivity I run my metal detectors at on the beach and in the water, "Running smooth" is usually my response. 
My smooth metal detector sensitivity control setting is always a reaction to the beach or water hunting conditions present as I start searching, I never not set my metal detector sensitivity control.
The only exception to this is when I use a screened metal detector with preset sensitivity levels that automatically compensate for changing ground conditions. 
Im my opinion, it is always better to set your metal detector sensitivity level when you get to the beach, it should not be a set and forget metal detector control setting. 
Many beach and water hunters are not aware that salinity levels can change dramatically at saltwater beaches.
If you are not aware of this, you may blame a chattery metal detector on offshore shipping or a beachside construction crane. 
Setting your metal detector sensitivity to suit the beach conditions present is easy, and it should be the first thing you do as you start metal detecting. 
Cover a little area in front of you, readjust your sensitivity control and repeat until you are confident you have your metal detector running smoothly. 
You are just fine tuning your metal detector to handle the saltwater beach, finding the highest setting that causes chatter and backing it off until your metal detector runs smoothly with the lowest amount of false signals.
When you set your metal detector sensitivity manually, strive to have your metal detector running smooth, not hot. 
There are now far too many other people using metal detectors at the beach, to run a chattery metal detector.
At heavily hunted beaches a smooth threshold may well be your best shot at detecting that find of a lifetime you are searching for.
An expensive solitaire diamond ring can easily be ignored as just a blip or chirp from water rushing over your search coil, or a soaked area of sand on the lower beach that a wave just washed over.
Under setting, or over compensating for the ground being covered can be just as bad as running your metal detector too hot.
That is why if you are not a "Tweaker" and do not tweak your metal detector sensitivity control to suit the conditions, you run the risk of missing valuable targets.
Running a metal detector with too low of a sensitivity level will cause you to miss deep targets or targets on the edge of detection range. 
I regularly use a Minelab Excalibur for beach and water hunting, the majority of Excalibur users I have ever met and talked to always have a preset sensitivity level, maybe that is why I like following other Excalibur users on the beaches I search at. 
When my wife says Im a sensitive guy, I look at some of the diamond rings she like to wear and reply, yes I am!