IFR and night makes the battery essential.

Even replacing the battery every year or two is cheaper than
a funeral.

I agree - although so far I've always been able to see an impending
failure thru charging current anomalies except when I've left the
master on......

On the other hand there just might be an infant mortality among 15 - 30
batteries that would have been needed to cover the 30 years I've had
this 172M. I'm glad I have a 12 V system though.