-To update the list of year numbers, add each year in which you change
-the package. (Here we assume you're using a publicly accessible
-revision control server, so that every revision installed is also
-immediately and automatically published.)
+To update the list of year numbers, add each year in which you have
+made nontrivial changes to the package. (Here we assume you're using
+a publicly accessible revision control server, so that every revision
+installed is also immediately and automatically published.) When you
+add the new year, it is not required to keep track which files have
+seen significant changes in the new year and which have not. It is
+recommended and simpler to add the new year to all files in the
+package, and be done with it for the rest of the year.
+
+For files which are regularly copied from another project (such as
+@samp{gnulib}), the copyright notice should left as it is in the
+original.