It would actually usually be the date of receipt of the notice which controls--i.e. the date you in fact got the notice. If you were supposed to receive notice within 10 days, for example, that would mean you get it by or before the 10th day.Sometimes it may be different to conclusively prove day of receipt; there may be occasions when the only date which can be established with certainty is the day the notice was sent, though in that case, unless it was sent by some instantaneous or same-day means (e.g. fax, email, messenger), it would usually be the case that 2 or 3 days would be added to reflect mail time.The least relevant date is the date typed on the notice letter itself, since that could be any date--someone could type February 20, or February 2, November 18th, or 1882, or 2037, etc.; that date is often useful to identify the letter/notice (i.e. "notice dated Feb. 20, 2012") but has no legal import.