If you've got the time at a site I like to dig those non repeatables. Like bighoss, I listen for a good signal mixed in with the iron or whatever signal, if it's there, I dig. I have recently found my oldest coin to date, an 1805 Draped Bust Cent, by digging one of those signals. It was in the hole with a square nail and another small piece of iron. I also found a nice 1835 hard times token in with several nails. I have found several other keepers that were iffy signals. You're going to dig a lot of just junk also by digging these signals, but to me it's worth it if every now and then you pull out a nice old coin. Again, you need a little more time to be able to hunt this way, and every hunt may not be conducive to this, but when you can, dig 'em. Good luck.
I would say it depends on your definition of "repeatable". If you get a tone over and over, in the same spot but its jumping around on the ID, I would say dig it- especially in all metal mode. No telling what you'll find?
Your MD will do its best to help you guess, an educated guess, at what's under there but you never really know till you dig. Now if you get the feeling it's trash like I do at times, you just gotta go with your best judgement or gut feeling etc.
Now if I'm running the ol Five in scrim mode, and the signal comes and goes, get a hit every 3rd swing and that kind of thing, I usually won't dig it. Sometimes I'll switch back to AM or notch back in iron when that happens just to make sure- but it all depends on what it tells me?!?! If you raise your swing and it leaves in AM - man I never dig those.
I've had some weird hits- I remember like a week after I got my MD- I was still in "dig everything" phase. I had a BB give me a pretty good wild goose chase. I had no pinpointer at the time. I must have looked in the whole, then the plug, then the whole ,then the plug for a good 30-45 minutes for that stupid thing- being me (stubborn) I was determined that I WAS FINDING, whatever was in there.....
I'm not really new to this anymore and I feel really comfortable with my F5 so needless to say I've learned a lot and don't have that attitude any more! Lol
If a target pinpoints large, it could be several coins spread out a little.Some of the deep signals I have been digging in my town...6inch at least don't always repeat/scream out. I usually only can get a good signal every few swings over it, if its small I have been digging them, I have dug 20 some wheats 2 mercs, and a quarter(silver) all in the last two three trips out. My half dime from the 1800's didn't repeat consistently either but dug it. If I get a good sound that is deep and it shows that its small during pi pointing it I dig it now.
When in doubt, dig it out.if there is any question in ur mind about a hit u get dig it doesnt take long could b junk or good u really dont have anything to lose but a minute or 2 good luck