Without another device to test whether it's a device problem or a service provider (voip.ms) problem, or an ISP problem, etc, there is no way to know why it's failing.
All I can say is, yes, hardware does "wear out" after many years, meaning that capacitors can degrade and fail, power supplies can go bad, and components can be degraded by repeated power surges.
If I were you, I'd wait for the inevitable "black Friday" sales and upgrade to an OBi 200.