If you're content with new coins, then "no park is hunted out". But if you're angling for old deeper park coins, and you're competing with pro's in your area, then the odds are, you might be looking at a park where you're going to have a hard time, as a newbie, to follow in their tracks and get "gimmees" that they missed. I can think of parks in my area, for instance, that we used to ..... back in the 1970s and into the early '80s, be able to get several silver and 7 or 10 wheaties, any day we wanted. Then it got down to 1 silver and a few wheats by the '90s. Now you've got to be a real pro. to get any more silver (unless someone does a park scrape const. job or something

So pity the newbie who comes along and wonders "where's the silver?"
Your best bet, if you're angling for old coins in a geographic zone with good competition, is to find areas they haven't hit. Yards of old homes is a good start, if you can start up casual conversation with folk out on their front porches

Especially 1940s/50s homes, since they're old enough to have silver, but have probably never been hunted before (pro's tend to seek out the older yards/sites). Once you get the knack for the deepies, then you can take those tones/sounds to worked out parks and have a better chance at finding those same patterns hiding amongst junk, deeper, etc...
And as for jewelry, you can certainly lower your disc, and dig foil and tabs in junky parks, looking for that evasive gold low conductor jewelry. Or, you can simply pick areas with better odds at jewelry to begin with: swimming beaches. Beaches have better jewelry ratios d/t the nature of people frolicking around in cool waters (where fingers shrink), or taking jewelry off for "safe keeping", and putting slippery suntan lotion on, etc.....