From Newbury, MA, the IDX is still a very desirable and easy to use machine. It won't be the best machine for wet saltwater sand but will do great everywhere else. The less sensitivity you use the better. You want to discriminate against iron only or you miss the chance of finding gold. Gold will come in from foil to coins. This isn't to say if your in a heavily trashy park your that you wouldn't want to raise it up a notch.
What I would recommend is picking up some paint stirring sticks. Attached some coins, jewelry, coins, nails, washers, bobby pins, foil, bottle cap, etc to the ends of the sticks (one per stick) and practice what your machine is telling you. Play with discrimination and sensitivity and see how things change. Once you get an idea how it reacts, go to the beach, easy digging. Stay up at the high end away from the wet sand but just below the towel line. Listen to every signal, see how steady, or how unsteady the meter is and then dig everything. What you will start to see is a pattern of your machine will talk to you for the good targets and how it trash talks for most of the bad. Don't get discourage, it all comes with time. In the spring, try some local school yards, ect. You will do good if you practice and stick with it.