Heater age?

[The_Barrs_Reef]

Hey everyone!
I am coming up on about a year and a half with my colbalt heater in my 120gal, my question is I hear you should switch them out about a year to a year and a half.
My question is it’s still running great as of now but should I go ahead and replace it or just get a second one and place it with it in case the older one decides to quit working? I also have it attached to a cut off if it gets too hot.

thanks in advance!

 

[theMeat]

Think it’s a good idea to have more than one heater, in tank, working, just in case. Also think it a good idea to have them on a controller. Would not trust the heater itself to control temp.
With that said have multiple heaters for over a decade without issue, but again I do not depend on heater itself for temp control