Depends on the usage.
Examples:
The subpoena's language was really hard to understand.
The subpoenas were served on the 27th.
I am does not need an apostrophe. It is only when you make it into a contraction by dropping the a that you need the apostrophe. It becomes I'm in that situation.
No. The Cannons doesn't need an apostrophe.
No, Christmas Eve does not need an apostrophe.
No, because plurals do not need an apostrophe.
As a plural, for more than one dad; no, does not need an apostrophe. As a possessive, as in the item belonging to dad, then yes, it does need an apostrophe.
No. Harringtons doesn't need an apostrophe.
The plural "Thursdays" doesn't need an apostrophe.
Lost wages doesn't need an apostrophe.
No, "Doc Adams" does not need an apostrophe unless it is possessive, such as "Doc Adams's bag."
do you need an apostrophe after the s in Koreans
No you don't! Horses does not need an apostrophe.
No, ours does not need an apostrophe (ever).The piano at the church had been ours.