The Writing Center, Ottawa, Canada says: "You should use an apostrophe to form the possessive case of a noun or to show that you have left out letters in a contraction. Note that you should not generally use contractions in formal, academic writing."
I've spent too much time recently thinking about the apostrophe. Our local newspaper editor had a thing against misuse of the apostrophe. However, I like the apostrophe when properly used. For example, it is essential to use the apostrophe in converting our Southern vernacular to print. The phrase "yallllvebeen", without an apostrophe, reads with the apostrophe "y'all'll've been", meaning "You (all) will have been." The apostrophe is needed in contractions involving personal pronouns. For example "ive","hed","well" need an apostrophe to be pronounced with long vowels "I've", "he'd", and "we'll". One problem with the apostrophe is in using it with possessive pronouns, as "it's", "our's", "her's". The editor's "Apostrophe Patrol" mostly concerned using the apostrophe to make proper names plural. as the "Jones's" instead of the "Joneses" and the "Brown's" instead of the "Browns
I am pleased to welcome you to my personal blog, which I started in March 2009. I first became interested in blogging about five years ago, using old "blogger.com", which was cumbersome to use and I never mastered. About a year ago I discovered that Google had bought "blogger.com" and had revised it considerably, making it fun to use, so much so that I have devised at least 15 blogs on various subjects and frequently add posts and Gadgets to them.