1) Write a select statement capturing the rows you want to modify and verify them by eyeball
2) (Optional) Modify that statement to select the unchanged rows into a temp table to be deleted in a few days
3) Wrap the statement from step 1 in a transaction
4) Modify the statement into the update or delete
5) Check that rowcounts haven't changed from step 1
6) Copy-and-paste the final statement into your ticketing or dev tracking system
7) Run the final statement
It may be overkill, but the amount of grief it can save is immeasurable
