I used to use AW IMR batteries (I've since moved on to LG HG2s). According to RTD Vapor, the cycle life of the AWs is over 500 charging cycles. I have four LG HG2s and two Sony VTC5s. I go through about one a day (my atomizers have a resistance ~1.2 ohms). If the cycle life is comparable and to be believed, and if I cycle through them religiously, I'll hit 500 charging cycles in over 8 years.
I don't think that I'll wait 8 years to replace my batteries. I'll certainly continue to monitor their capacity to hold a charge and I would expect to see a drop before then. Otherwise, 3 months seems too short of a period to me to replace batteries (unless they are damaged). I was thinking of doing so after 3 years if I didn't notice a significant drop in performance.