Entirely, Silver is very soft and wears very quickly. Especially if it was in a humid climate or warm place. Mainly tropics and subtropics, but also you guys in the USA as even in the north and east, you had hot summers!
My own studies show that silver coins of NZ minted in 1933 - 1946 are mostly found in G and VG condition, Fine is less common and VF is a premium, EF and better are very scarce and prices reflect this.
Average to slightly better than average NZ coins.
Most only circulated 10 - 15 years to go from UNC down to VG, some may have been used up to the 1960s before we went decimal, but to pay WW2 loans to UK and USA, as much silver as possible was ferreted out from 1950 onwards.
Cupronickel has survived better, you would be hard pressed to find even a 1947 coin in less than Fine or almost Fine
A lot of standard scrap 1947 - 1952 KGVI cupronickel of NZ, most are Fine heading up to VF, some stained. Many were used 20 years to 1967 and some 6d, 1/- and 2/- circulated through to 2006 and still remained fine.
Bronze is more durable than copper, many bronze pennies remained recognisable back to 1900 (UK, NZ pennies from 1940 onwards are always F - VF and EF for 1960s). Only Bun head pennies from the 1890s backwards are flat discs mainly as they were low relief.
Standard worn flat Bun head penny, this coin probably spent 100 years in criculation
Standard penny from 100 years ago (Spent about 50 - 60 years in circulation, yet still VG - Fine condition).
I would say silver coins wore very fast. My guesses of standard times assuming the coin was a Quarter or a Shilling and used heavily in an urban context in 1900.
Condition and Days
UNC - Leaves mint, may have marks already from bulk carrying
AU - A couple of days of rough handling, week in a till.
EF - 2 or 3 weeks rough handling, 2 months in a bank being counted
VF - Maybe 2 months continuous wear, 1 year in nicer situations
Fine - less than a year since minting for constant usage. 10 years at most unless put aside or not used much.
VG - 5 years constant usage, coins wore much slower when they got really worn. Most coins got this bad before recalled or in someones collection 100 years later.
Good - 20 or more years rough usage, never if well handled.
Fair/Poor , at least 80 or more years rough usage.
Just my guesses!
Loving Halfcrowns. British and Commonwealth coins 1750 - 1950 and anything Kiwi.
If it's round, shiny and silvery I will love it.