No
You would capitalize that word however you use it.
The pronoun,I is always capitalized.
Yes, "Internal Revenue Service" should be capitalized as it is a proper noun.
No, "memorial service" is not capitalized unless it is at the beginning of a sentence or part of a title.
This means exactly that. Thanks, for whatever gift/service was given.
No it shouldn't be capitalized in this instance.
Yes, President is a title just like professor. Its acceptable to not capitalize these words when they are not describing someone. EX: the history professor is really difficult. But when it is not a noun, and is however, a pronoun you should capitalize it. With the exception of President and Doctor. These should for the most part always capitalized.
My best Dictionary says a veteran is someone who has long service or grew old in the military.
Tell the person to return it to the front desk
At the begaining of a sentence, and the first letter of someone's name.
Faith is not a proper noun. If someone is named Faith, then it is capitalized.
You only need to capitalize the word "billion" if it is the first word of the sentence...or if it is actually someone's name, or any other proper noun.