Advice of Lipo IR.

Hi,
I've got a pair of Trakpower 4900mah 7.4v lipo for around 2 years.
Recently I charged them with Hyperion chargers and the IR.of the batteries are 25 mOhm and 30 mOhm in 4.5A charging current.
I want to know if the batteries get tired or not?
I know it best to know the answer by Eagle Tree but I have none.
Please reply the advice and reference from you guys.
For lipo operation I'd rather to keep a safe margin.
I don't want to tell tired batteries from flame in my truck.