http://www.englishclub.com/vocabulary/contractions.htm

This is something that I think all style manuals agree on: you cannot use contractions. Is it that it makes it look more professional? Probably. But I do know that it is much more difficult to write this way, not to mention it is a major pain when you lose points over it. The only positive aspect of using contractions is that you increase your word count. This means that it looks like you spent more time doing work that took you a fraction of a second. I've made a lot of dumb mistakes over using contractions, and there are some that annoy me, such as should've or could've. I see them all the time, which probably aren't even words, and some people go so far as to butcher it into "should of" instead of "should have." Thanks, phonetics!

One other nice thing is that it is nearly impossible to mix up you're and your or they're and there. However a threat still exists wherein you write "there" instead of "their" or if you are just so dumb you really think "your" is correct. Which could be true. It is particularly easy to find this errors, luckily. Honestly I do a search find and replace protocol whenever I write an essay over a couple of pages long (profs do not seem to care about that much if its that short) for "can't" "don't" etc.

I think this is a relevant and important discussion. So, what do you think about contractions? Should we use them or should they continue to be outlawed in most styles of writing?