Final answer:
In English grammar, geographic names such as 'Idaho' must be capitalized as they are proper nouns. General nouns like 'cousins' are not capitalized unless they start a sentence or are part of a title.
Step-by-step explanation:
Capitalizing geographic names is important because it follows the rules of proper nouns in English grammar. When referring to specific places like states, countries, and cities, the names must be capitalized. For example, when you say 'Every year, I visit my cousins in Idaho.', the word Idaho should be capitalized because it is the name of a state. However, general nouns like cousins should not be capitalized unless they are part of a title or it is the first word of a sentence.