I think that plays a large part in when she posts content. For instance, she recently posted a picture dump on August 18th, which aligns with those sub-renewal dates. I believe she’s trying to do two things: post roughly around (but before) sub-renewal dates to retain some of those subscribers, while also posting the bare minimum amount of content she’s willing to in a given month to maintain the illusion of activity on her OF page. By timing those posts just before renewal dates, she can also target subscribers who may be considering unsubscribing and give them a reason to stick around for another month. Or maybe I'm giving her too much credit...