Take the following example.
Your boss requests you to create a table of who sent you the most emails yesterday. You go through your inbox and count for each name, adding a row each time you start counting a new person. You sort from high to low at the end and present the summary. Then your boss asked who sent you the most yesterday morning. Back to square one to pull the dates, even through you reviewed that same population.
If, instead of extracting summary counts for each name, you made sure to Collect data in the rawest form, Let a program do the heavy lifting and you Make raw data accessible when continuing summary iterations, you could revisit the raw data to append additional information to each record and easily inform new summaries.
Said differently, The summary should never be the rawest form of data.
It can be applied to data or writing. I have also encountered From fragments you can build a greater whole and the artwork Bits and pieces put together to present a semblance of a whole