Usually the worst critic of your own code is yourself. There is enough of the attitude that we can do nothing wrong that we do. Documentation is the characteristic of a thorough programmer who remembers the consequences that happened when he or she didn't remember what the prior modification was for. It also helps to add a date stamp of when it was added, to the right of each line of code, with the which ties back to a short paragraph of comments at the beginning of the module describing the reason for the change.