Collectible coins are often categorized by their historical significance, rarity, condition, and demand among collectors. In the United States, coins such as the 2005 Denver-minted dollar coins can be part of series like the Presidential Dollars, which commemorate U.S. presidents. A "1 Roll" typically contains 25 coins, providing a convenient way for collectors to acquire multiple examples of a specific issue. The condition and minting year significantly affect the coin's value and desirability in the marketplace.