My last two Interstate Mega-Tron batteries have both lasted 7 to 8 years in my ERA and probably would have lasted longer had I not broken down and replaced them. And I performed
no maintenance on them whatsoever during all that time. Never even looked at the water levels. I would occasionally peek at the terminals to see if there was an abundance of that funky white stuff on them, but there was never enough to warrant doing anything so that's it. I wouldn't replace the battery in there with anything else.
