how often should belt be replaced at what cost ,what could be damages if I don’t.
Serpentine belt or timing belt? Also your owners manual would have that pertinent information
Depends on where you live
Depends on the belt and whether you have an interference engine or a non-interference engine
If the timing belt breaks, the engine will be severely damaged. This IS an interference engine.
If has never been done, you are due now - 13 year old belt is not a good thing!
Dodge suggests the tensioner and the water pump be changed at the same time.