I knew about the AGM battery recommendation, but I didn't realize WHY. I thought the reason to get a "maintenance free" battery was so you don't have to do maintenance on it. While that's true, there's a better reason to get an AGM battery if you have a VN750. It's because our charging system is -- well, some say it's bad. You could also say it's got character.
At any rate, it seems to be more successful at keeping an AGM in good shape than it does with a conventional battery. But since I didn't understand that, and my conventional battery seemed to be just fine (meaning it had the volts to start up the bike, at least the first time, and it had enough cranking volts also), then I didn't think I needed a battery yet. And I figured I would just replace it with an AGM whenever I needed to replace it.
But what I didn't realize was... whenever you don't have an AGM battery on a VN750, the time to replace it is "right now."
I put an AGM in my bike about a month ago, and it's been great ever since.
I know somebody will correct me if I've said anything wrong here.