diff --git a/au/quantity.hh b/au/quantity.hh
index 59d6207f..577b829c 100644
--- a/au/quantity.hh
+++ b/au/quantity.hh
@@ -113,9 +113,6 @@ class Quantity {
     using Unit = UnitT;
     static constexpr auto unit = Unit{};
 
-    static_assert(std::is_arithmetic<Rep>::value,
-                  "Rep must be built-in numeric type for now; see #52");
-
     // IMPLICIT constructor for another Quantity of the same Dimension.
     template <typename OtherUnit,
               typename OtherRep,
diff --git a/docs/alternatives/index.md b/docs/alternatives/index.md
index 7e7d773e..3cef9ee9 100644
--- a/docs/alternatives/index.md
+++ b/docs/alternatives/index.md
@@ -547,10 +547,13 @@ features.
             <a href="https://mpusz.github.io/units/reference/core/concepts.html#_CPPv4I0EN5units14RepresentationE">Representation
             concept</a>
         </td>
-        <td class="fair">
-            Rep can only be <code>is_arithmetic</code> for now, but
-            <a href="https://github.com/aurora-opensource/au/issues/52">plan
-            to upgrade</a>
+        <td class="good">
+            <ul>
+                <li class="check">Mature support for <code>is_arithmetic</code> Rep</li>
+                <li class="check">Experimental support for custom Rep</li>
+                <li class="x">No constraints yet (<a
+                href="https://github.com/aurora-opensource/au/issues/52">#52</a>)</li>
+            </ul>
         </td>
     </tr>
     <tr>