This OID records how long ago (in milliseconds or seconds, stored as TimeTicks) this route was first learned or last refreshed by the routing protocol. Engineers monitor route age to detect stale routes that may need to be flushed from the table or to confirm that dynamic routes are being continuously refreshed and remain valid. For example, an age of 0 ticks means the route was just learned moments ago, while an age equal to the route timeout limit (typically 180 seconds) means it is about to expire and disappear.