Hi anonymous,
Timer usage is to synchronize the ENB and UE. Say example DRX timer, If UE is not maintaining DRX timer then UE cant predict when to wake up and when to sleep.same way in ENB side If ENB didn't maintain timer then ENB cant predict when to send paging and when to send data. So in order to synchronize the ENB and UE we are (LTE) maintaining the timer. If timer is not there means there is no mechanism to synchronize the ENB and UE.
Happy Learning :)