How does a coin collector determine the value of Canadian and US silver coins?

Answer 1

A quick overview:

They have to determine at least 4 things about the coin:

Its date, its mint mark, its condition, and whether it is genuine.

The first two are easy, the third is subjective and the fourth can be difficult.

There are books like Photograde that show images of coins that experts have graded according to how worn they are, and by matching a coin to the nearest picture it's possible to get a good idea of how its condition will rate.

For uncirculated and proof coins there are additional criteria related to the coin's condition that are the province of numismatic grading experts, many of whom have to pass qualification exams or otherwise become certified graders.

There are many counterfeit coins on the market, so in many cases it's also necessary to look for signs that a coin is fake. E.g., sloppy lettering, incorrect weight or size, etc. Like looking for forged paintings, it can be a very difficult task to sort out real coins from skilfully-made fakes.

Various companies publish current market values for coins (see for example Numismedia.com) that can be used, a bit like the stocks pages in a newspaper, to determine what the current selling and buying prices are for each item.