Learn English – “Yours” as valediction

When working in England, I've found that "Regards" is most common, even amongst parties that have a good relationship.

When working in Australia, "Best regards" is much more commonly used. Using simply "Regards" would seem quite standoffish.

I'm not sure which is most applicable in Denmark.

John S. Locke states in The Art of Correspondence (1884):

In closing a letter never subscribe yourself Yours, &c. &c. is an abbreviation of etc., which is an abbreviation from the Latin words et cetera, meaning and others, or, and so forth; forth means onward or forward. Hence there can be no propriety in saying I am yours and others, or I am respectfully yours and onward. This awkward expression is very common in business letters. Printers frequently abbreviate the complimentary closing of a letter, and to save type or time they print Yours, &c, which implies that the letter is closed in the usual form. Doubtless some thoughtless writer seeing this, concluded that it looked well and gave the letter an air of business despatch; hence it came into its present improper use.

If Mr. Locke is correct, the appearances of &c. in Pride and Prejudice may have been nothing more than a way to reduce the required typesetting.

Even though he states that &c. indicates that the closing is of the "usual form," there is no one usual form. For business letters he lists many possibilities:

Yours truly; Truly yours; Respectfully yours; Yours respectfully; or, if it is desired to give more emphasis, the adverb very may be added, as, Very truly yours; Yours very respectfully.