Ruby Port- they are the youngest Port Wines, therefore there Oxidation* Process is faster, in order to get the best of this wines, theres a limit for consuming after opening of about 2/3 weeks (not one week).
Lbv- (late bottled vintage)- they are some of the oldest Port wines, the contact with air (oxidation) took place several years, so the wine is naturaly protected agains the air..their consumption after opened is about 1 week, but even if opened 2 or 3 months will be dificult to understand if they are changing..doesnt afect the taste, afect essentialy the colour..so keep it for 2 months after open!
Vintage-(the highest status on port wines) depending on the (vintage) = year of harvest, we must acount also bottling date, young port means faster oxidation after opened, older means slower oxidation after open..example: Vintage 2011 bottled in 2013 is consider a Young Port, so consume faster! Vintage 1985 bottled in 1987 if we open now 2014 means 27 years of bottle stage, therefore contact with oxigen during that period the wine becomes protected naturaly..so consume within 3/4 months!
Tawny- there are younger and older tawnys, minimum aging period to become a Tawny is 7 years, the oldest ones 10,20,40 years Old, they are extremly resistent and period of keeping after open can exceed 5 months after open!!