It is good to be confident about your work. However, do not be too confident, just take another look.
Being involved on the project management field, especially in the construction planning taught me the value of accuracy. I am dealing with numbers, figures, and percentages. Analyzing huge amount of date in order to report maybe a single number or percentage to my manager.
All my efforts could go away if the final result was wrong. Senior management do not care about what I did, they only care about what they have between their hands. Therefore, I have learned after I finish an important report to take a breath, stay back and maybe doing something else for few moments, then return back to my report as I am reading it for the first time without knowing what is inside. In this case, most probably, I will find something to edit or tune it up before submitting my final report.
The conclusion: Just give yourself a chance to review your work, before someone else does.