diff --git a/doc/TODO b/doc/TODO
index c06c7dc5ad..176d6ca4ff 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -31,7 +31,11 @@ Things we'd like to do in 0.2.0.x:
       o Change guard calculation
       o Change dir-spec.txt
       - What should we do about hosts that have been up for only 1 hour,
-        but have been up for 100% of that one hour?
+        but have been up for 100% of that one hour? -NM
+        Perhaps the guard flag should only be assigned if the measurement
+        period for that server is at least some large period, like a
+        week; but ignore this exception if "most" servers have too-short
+        measurement periods. -RD
     D 118 if feasible and obvious
     D Maintain a skew estimate and use ftime consistently.
     - 105+TLS, if possible.