In the 12+ years that I have owned my 2003 M45, I have gone through a battery just about every 3 to 3.5 years max. Because they died and stopped cranking. In the beginning, I used OEM for the first two or three replacements, but the next-to-last time, I tried an Interstate top of the line Megatron Plus MTP-24 and it lasted just about as long as the average Nissan/Infiniti OEM ones.
Unfortunately, I had no choice but to get another Interstate Megatron Plus since I was trying to replace the first one under warranty at their store (no luck

, since they wanted to keep the battery overnight to "test it" and I needed a battery right then since my car was dead).
If this one goes as quickly, then I will be irritated again.
Z