HSRP track object is a really cool stuff to modulate behaviour of HSRP.
This kind of object is usually used by means of ’line-protocol’ feature. You can change Active Virtual Router, if an upstream interface comes down.
Such as :
DWS1(config)# track 20 interface FastEthernet 1/13 line-protocol
DWS1(config)# interface fa 1/13
DSW1(config-if)#standby 10 track FastEthernet 1/13 60
If FastEthernet 1/23 comes down. HSRP priority is decremented by 60.
But, you can use track object with condition on routes. Object reacts when it is and is not between some values. These values are scaled because of different kinds of metric. Imagine EIGRP and RIP metrics. It is so different. It is due to this, we seed metric in redistribution and here we scale it to be able to make condition on routes.