I had a 1710AV that I felt the same way about. Still my favorite monitor to this day. One day, I turned it on and heard a "pop." It never worked again. 

The longevity question is similar to the same question about the Macs themselves -- shut them off, or keep them on? With Macs, I'm pretty firmly in the "leave them on" category, if you use them regularly. I suppose it'd be the same with CRTs. The initial surge of electricity when they turn on is probably harder on the components over time than just sitting idle. 

But I don't really know. I still have several CRTs left, small and large, but I haven't turned any of them on in years.