diff --git a/tools/tinderbox/build-seamonkey-util.pl b/tools/tinderbox/build-seamonkey-util.pl
index 1a2f71ea509..a83e52d1a94 100644
--- a/tools/tinderbox/build-seamonkey-util.pl
+++ b/tools/tinderbox/build-seamonkey-util.pl
@@ -24,7 +24,7 @@ use Config;         # for $Config{sig_name} and $Config{sig_num}
 use File::Find ();
 use File::Copy;
 
-$::UtilsVersion = '$Revision: 1.338 $ ';
+$::UtilsVersion = '$Revision: 1.339 $ ';
 
 package TinderUtils;
 
@@ -144,6 +144,7 @@ Options:
   --config-cvsup-dir DIR Provide a directory of configuration files 
                           (mozconfig, etc.) to run a "cvs update" in before 
                           a build begins.
+  --interval             Limit this build to building once every N seconds
   --version              Print the version number (same as cvs revision).
   --help
 More details:
@@ -179,6 +180,7 @@ sub ParseArgs {
             -t BuildTree
             --mozconfig MozConfigFileName
             --config-cvsup-dir TboxBuildConfigDir 
+            --interval BuildInterval
         );
         if (defined $args_with_options{$arg}) {
             my $arg_arg = shift @ARGV;
diff --git a/tools/tinderbox/build-seamonkey.pl b/tools/tinderbox/build-seamonkey.pl
index 25d242d79ae..0478600f3c4 100755
--- a/tools/tinderbox/build-seamonkey.pl
+++ b/tools/tinderbox/build-seamonkey.pl
@@ -12,11 +12,28 @@ use strict;
 # They are not initialized here. The default values are after "__END__".
 $TreeSpecific::name = $TreeSpecific::build_target = $TreeSpecific::checkout_target = $TreeSpecific::clobber_target = $::Version = undef;
 
-$::Version = '$Revision: 1.103 $ ';
+$::Version = '$Revision: 1.104 $ ';
 
 {    
     TinderUtils::Setup();
     tree_specific_overides();
+
+    # This code assumes that the build process will alter the mtime of the
+    # "build directory" (i.e. WINNT_5.2_Dep, Darwin_8.1.0_Clbr, etc.) by
+    # dumping a log file or some such in the directory. If that's not the
+    # case, then this "feature" won't work.
+    if (defined($Settings::BuildInterval) && $Settings::BuildInterval > 0) {
+        print STDERR "Build interval of $Settings::BuildInterval seconds requested\n";
+        my $lastBuilt = (stat($Settings::DirName))[9]; ## Magic 9 is st_mtime
+        my $now = time();
+
+        if (($now - $Settings::BuildInterval) < $lastBuilt) {
+            print STDERR 'Last built at ' . scalar(localtime($lastBuilt)) . 
+             ', ' . ($now - $lastBuilt) . " seconds ago; not building.\n";
+            TinderUtils::stop_tinderbox(reason => 'Build interval not expired');
+        }
+    }
+
     TinderUtils::Build();
 }