The Apostrophe is not invited to a Plurals party.
However, roll out the red carpet for the Apostrophe for the Possessives and Missing Letters gala.
Apostrophe = ownership = e.g., Dana’s car, Jamal’s class, Sharon’s plays
Apostrophe = missing letters between two word = e.g., can’t as in can not, isn’t as in is not, don’t as in do not, it’s as in it is
And then, there is the matter of apostrophes in names:
Last name apostrophes = don’t do it = plural = e.g., The Stewarts went to church. The Johnsons bought season tickets. The Mears sent the kids to summer camp.
Last name apostrophes = do it, after the plural comes the possessive = e.g., the Stewarts’ party, the Johnsons’ vacation, the Mears’ home
Lastly, years are plural, ergo the apostrophe is not invited, e.g., 1960s– no, not, and never 1960’s.