Okay, okay, I'll go into more detail. The #1 mistake I see on this subject is last names. Say your last name is "Smith" and you'd like to sign a note from your whole family. You simply add an 's'. No need for an apostrophe, but somehow, I frequently see it written as:
I knew it was getting bad because I saw this everywhere. And then I saw it on regular words. Take the Etsy forums, for example. People want to talk about more than one treasury, so guess what they make it. "Treasury's"
Can you tell I'm in a cranky mood tonight? I suppose I'll always come across in a 'holier than thou' way when correcting. It's just a natural result, but I truly do want to help small online business owners.
I cannot say this enough: When you own an online business, your written language--your spelling, your grammar--is how you present yourself.
Pluralization is quite simple. Add an 's' to make more than one.
When your word ends with a 'y', you need to take out the 'y' and add 'ies'.
Don't over think it.
Apostrophes, in general, are only used for contractions and to show possession.
Something that belongs to someone: The boy's hat.
When there are two or more boys with hats, the apostrophe follows the 's': The boys' hats.
Did not becomes didn't.
Should not becomes shouldn't.
The apostrophe (often) takes the place of the one missing letter. (The 'o' in 'not' in the examples above.)
Any comments? Questions? Promises you don't intend to keep?
I'm here. Let me know if you have a question about spelling, grammar, punctuation, and the like.