The apostrophe catastrophe

You can't swing a cat these days without hitting a sign that uses the arduous apostrophe incorrectly. Even book titles and newspaper headlines have been caught in the act. But despite its widespread misuse, the rules aren't as complicated as they seem:

Rule 1:
Apostrophes are used in contractions to call attention to a missing letter or letters:

• I can't instead of I cannot
• I shouldn't instead of I should not
• It's instead of it is

Note that the word 'its' ONLY HAS an apostrophe if it is a contraction of 'it is'. There is no apostrophe when ownership is concerned:

• The cat ate its food.

Rule 2:
Apostrophes are used to call attention to possession:

• The ship's sail
• The company's logo

If there are two ships or companies, the apostrophe comes after the s:

• The ships' sails
• The companies' logos

Rule 3:
Apostrophes are never used to denote plurals.

• Car's for sale should read Cars for sale
• Tire's changed while you wait should be Tires changed while you wait
• Buy your CD's here should be written Buy your CDs here
• He reached his peak in the 1960's should be written He reached his peak in the 1960s