Turns out that this condition in `check_expired_networkstatus_callback()`: ``` if (ns && ns->valid_until < now+NS_EXPIRY_SLOP && router_have_minimum_dir_info()) { router_dir_info_changed(); } ``` ... is always true if we have all our needed directory info which means that `router_dir_info_changed()` is called every 2 minutes (the callback interval). Nick suggested that it should be `now - NS_EXPIRY_SLOP` which goes like this: If `valid_until` is 6am today, then `now - 24h` == 1pm yesterday, and `valid_until < (now - 24h)` is false. But at 6:01am tomorrow, `valid_until < now - 24h` becomes true.