I tend not to use contractions in my writings. For example, I prefer to write "He will" and "He has" instead of "He'll" and "He's". And when I do use contractions, I only use them when I write dialogues. For example, a lot of people tend to say "Letz" instead of "Let us," so I use "Let's" if I think that is how a character would pronounce that word. I understand that it is a literary norm to use contractions, but is it WRONG if I don't want to?