My son (who is now 20) is named Zachary, but we usually just call him Zach. For about his first year, we spelled it "Zack". But, then I started thinking about what it would be like for him to learn to write his name. I thought it might be confusing for him to use a "k" if he was writing Zack, and then an "h" if he was writing Zachary. Not a huge dilemma, I know, but we decided to go with the spelling of "Zach" to simplify things. I am so used to it now that I can't imagine spelling it any other way!