diff --git a/sbin/dhclient/dhclient.conf.5 b/sbin/dhclient/dhclient.conf.5
--- a/sbin/dhclient/dhclient.conf.5
+++ b/sbin/dhclient/dhclient.conf.5
@@ -78,6 +78,14 @@
 results in fairly timely updates without placing an inordinate load on
 the server.
 .Pp
+The
+.Ar time
+parameter in this section is in seconds.
+The value can be specified as decimal, octal, hexadecimal,
+or negative literals.
+Negative values may parse but behave unpredictably,
+and should be avoided for timing values.
+.Pp
 The following statements can be used to adjust the timing behaviour of
 the DHCP client if required, however:
 .Bl -tag -width indent