Overdrive...?

I was never quite sure about Overdrive. I recently bought a 97 Maxima GLE , AT, and I was wondering if it would be best to leave the OD on or off. I've read so many contradicting things online that I'm not sure which way to go.

I read that if you live in a hilly area that it should be off or else it'll damage the transmission. Is that true?

Anyway, on or off? What do you guys think. Thanks in advance.

I keep it on, against 'recommendations'. In towing, off. When it starts oscillatin (up the hill, very seldom) then its better to be off.

The only thing is true that one day it will be dead, no matter what :(
Changing ALL oil is important; at least once in 2-3yrs, NOT like recommendation in Nissan Factory Manuals 1/4 swap. Some links http://www.cardomain.com/ride/748507/24