I did some research on this and would like to share.
Jagers are not what they used to be. I have two that both leaked and died. Didn't use for more than a few years. On the other hand, older models seem to last decades. That seems to be the consensus online.
I settled on the new Stealth Pros. Sure, older models have been known to melt. So, I limited myself to 25W and 50W heaters at about 1W/gallon. It's enough to lift the tank temperature a few degrees, which is all I need. Lamps and pumps provide most of the heat, and the heater serves to just stabilize the temperature.
The other important trick (especially with Jagers) is to not completely submerge the heaters and keep the heads above water. It's troublesome but should virtually eliminate leaking.