The Sentence Sleuth says you need to balance all the elements of your sentences.

I don’t know about you, but I was glued to the Olympics this year. And I’m not embarrassed to announce that I watched many hours of gymnastics, synchronized diving and synchronized swimming. You have to admire the athletes’ amazing precision, excellent balancing and graceful landings.

If only writers were as precise, balanced and graceful as these medal winners. If they were, readers could happily wend their way down a logical, parallel path, enjoying elegant sentences whose parts match each other. Parallel elements have the same weight and are often the same part of speech. Noun, noun, noun. Check. Adjective, adjective, adjective. Yep. Verb, verb, verb. Parallelism is all about equality; parallelism creates a nice rhythm in your sentence; unparallelism, bad. Adjective, adjective, verb. Yikes. Noun, adjective, adjective. Insert sour-faced judge here.

For more: http://writersdigest.com/article/using-parallelism-in-your-writing/