Recently we have had some turnaround in the shop I work in, because of this comments in our source code were made hastily and explained very little. We have started working on the departments first draft of coding standards and one of the bigger questions is: Should we implement this standard across the existing source code? Since this is only our coding standards first draft (done to promote flexibility and future considerations), should we be implementing on new features and during maintenance?
Update: I would like to say thank you for all of the answers and comments that were received on this topic. Our shop has started to move forward with developing a draft for our coding standards and we have taken bits and pieces from all of the comments and answers to work with throughout our process. Thank you for your time and experience on this matter.