diff --git a/best-practices/README.md b/best-practices/README.md
index 7a6e5fed..f547ff82 100644
--- a/best-practices/README.md
+++ b/best-practices/README.md
@@ -165,6 +165,9 @@ Postgres
 * Consider a [partial index] for queries on booleans.
 * Constrain most columns as [`NOT NULL`].
 * [Index foreign keys].
+* Use an `ORDER BY` clause on queries where the results will be displayed to a
+  user, as queries without one may return results in a changing, arbitrary
+  order.
 
 [`NOT NULL`]: http://www.postgresql.org/docs/9.1/static/ddl-constraints.html#AEN2444
 [combines multiple indexes]: http://www.postgresql.org/docs/9.1/static/indexes-bitmap-scans.html