diff --git a/doc/sphinx/arm/classify.rst b/doc/sphinx/arm/classify.rst
index 9f279454b7..aaa2e52770 100644
--- a/doc/sphinx/arm/classify.rst
+++ b/doc/sphinx/arm/classify.rst
@@ -920,7 +920,10 @@ hex string (which would indicate a DUID based on an enterprise ID of
    }
 
 It is also possible to have both left and right operands of the evaluated
-expression processed at runtime.
+expression processed at runtime. Expressions related to packets can appear in
+the expression as many times as needed. There is no limit. However, each token
+has a small impact on performance and exceedingly complex expressions may be a
+major bottleneck.
 
 ::