Depends on where you're hunting, and what you're hunting for. And your tolerance for junk, blah blah blah.
Since it already has a crude TID screen (cursor bouncing in and out of categories), you can always set it to low disc. settings, in disc mode (to accept all items) and simply use your eyes to see where thing come in at, to decide if you want to dig it or not.
If you want gold jewelry, you're going to have to dig things in the foil/nickel/tab range. If that's too punishing, and you find yourself digging 100+ foil wads and tabs without a single gold item to show for it, it means you are not in an area that is good for gold jewelry hunting, to begin with. Ie.: don't go to junky blighted urban ghetto parks, lower the disc, and think you're going to find gold jewelry (without first going mad). Instead, pick locations where gold jewelry ratios will be better, and that, by their nature, are more productive for jewelry losses. Namely: sandy swimming beaches. Doesn't need to be ocean beaches either. Can be inland freshwater swim beaches. Preferably in the water (in the case of lakes), but above water is ok too.
Or if you want to cherry pick for silver coins in park turf, then you might choose to be a little more selective, and pass surface foil, shallow zinc, etc....
So it all depends on where you hunt, your junk tolerance, and what you want to find.
