assign log messages a status and decide in the config which log level you want to log.
example:
replication pairs always output the next pass - thats 2 to 3 lines every 2 seconds.
running the daemon in --quiet suppresses messages i would want to see but still outputs replica log messages every 8-12 seconds like:
Fri Apr 23 15:46:52 repl: applied 1 operations
Fri Apr 23 15:46:52 repl: end sync_pullOpLog syncedTo: Fri Apr 23 15:46:52 2010 4bd2073c:1