All licenses shall expire and be void after the date of expiration specified on the license, except that when the day of expiration of a license falls upon a Sunday or a holiday, the license shall be valid until the next business day.
Business licenses shall run for twelve (12) months from the first of the month in which the license becomes effective.
Occupational licenses shall run for two (2) years from the first of the month in which the license becomes effective.
D.C. Mun. Regs. tit. 17, r. 17-205