You have to remember that where is a continuum and that metal is relatively hard. So according a coin doesn't just pop out of the roll or bag and become instantly circulated...
Nevertheless the finest details are not that robust and it doesn't take long for the signs of circulation to appear on the coin.
So that's what you have to train your eye and train your mind to see... Once you know the very highest and most fragile points of a given coin series you'll learn to recognize wear.
If you're playing with older coins you need to learn the difference between wear and a weak strike... It's a subtle thing but it will show as the higher points not evenly filled out versus the very highest points.
For example on a
Morgan dollar the highest point of the Eagle's breast feathers will show where as will the upper edge of the wing. A weak strike which you might see in say 1890s New Orleans coins, the whole of the breast is just indistinct.
It's something you have to learn and learn by looking at lots of coins.
-----Burton
50+ year / Life / Emeritus
ANA member (joined 12/1/1973)
Life member: Numismatics International, CONECA
Member: TNA, FtWCC, NETCC, EveryCountry (online) coin club
Owned by three cats and a wife of 40+ years (joined 1983)
Author: 3rd Edition of the Sample Slabs book,
https://www.sampleslabs.info/