diff --git a/R/geom-defaults.R b/R/geom-defaults.R
index b185990fbb..732f5ddb32 100644
--- a/R/geom-defaults.R
+++ b/R/geom-defaults.R
@@ -11,7 +11,17 @@
 #' @keywords internal
 #' @note
 #' Please note that geom defaults can be set *en masse* via the `theme(geom)`
-#' argument.
+#' argument. The guidelines for when to use which function are as follows:
+#'
+#' * If you want to change defaults for all geoms in all plots, use
+#'   `theme_update(geom = element_geom(...))`.
+#' * If you want to change defaults for all geoms in a single plot, use
+#'   `+ theme(geom = element_geom(...))`.
+#' * If you want to change defaults for one geom in all plots, use
+#'   `update_geom_defaults()`.
+#' * If you want to change settings for one geom in a single plot, use fixed
+#'   aesthetic parameters in a layer, like so: `geom_point(colour = "red")`.
+#'
 #' @export
 #' @examples
 #'
diff --git a/man/update_defaults.Rd b/man/update_defaults.Rd
index 777182e24f..9620dde4e1 100644
--- a/man/update_defaults.Rd
+++ b/man/update_defaults.Rd
@@ -31,7 +31,17 @@ Functions to update or reset the default aesthetics of geoms and stats.
 }
 \note{
 Please note that geom defaults can be set \emph{en masse} via the \code{theme(geom)}
-argument.
+argument. The guidelines for when to use which function are as follows:
+\itemize{
+\item If you want to change defaults for all geoms in all plots, use
+\code{theme_update(geom = element_geom(...))}.
+\item If you want to change defaults for all geoms in a single plot, use
+\code{+ theme(geom = element_geom(...))}.
+\item If you want to change defaults for one geom in all plots, use
+\code{update_geom_defaults()}.
+\item If you want to change settings for one geom in a single plot, use fixed
+aesthetic parameters in a layer, like so: \code{geom_point(colour = "red")}.
+}
 }
 \examples{