We learn in school that contractions can be a writer's (or typist's) friend. They can be wonderful short-cuts when composing, especially if one is a wordsmith in poetry and meter. Contractions are also a great way to write with a more friendly, homey/folksy style, which can be great for blogs and other personal notes and messages.
However, when writing for a wider audience, as many of us aspire to do here at OMTimes, please be mindful of your use of contractions, especially if you desire your work to be included for publishing. I find it is one of the main changes made to submissions, honestly.
If it helps to look at it another way, for those writers who struggle to make word count, not using contractions turns one word into two, like magic! It may also help in getting your message across clearly. Realizing we can all be rushed for time, it is worth it to review your words to make them the best they can be. In this way, we can find a happy balance between quantity and quality!
Trevor has shared many helpful hints and tips here in the Workshop, and newer writers are encouraged to explore them. I am grateful to read everyone's submissions--keep 'em coming! ~ Blessings!