That is a pretty open ended question
It really depends on how many changes your site has gone through, and what your objectives are.... and also, how many people are using the report....
I sometime just start a new report from scratch.. this gives me time to work on it without impacting other people.. when I am happy, I will review the report with stakeholders...
Finally, sometimes this means just transitioning users to the new report... or copying my panels over to the old report and removing the old content (so that everyone's links and permission levels stay intact)
