Guess I owe you guys an update.
I did take K a few times recently, partly because I like it so much, and partly because I wanted to get to the bottom of this instead of wondering forever what's the deal with K and my bladder. I did take K less often, though, and in lower doses than usual. Basically 1 bump on a given night, instead of multiple. There were, however, a few occasions since it's summer and festival season and what not.
Current impression is I have reduced bladder capacity the day after or so. Sometimes I get a very sudden and distinct urge to piss, like when getting groceries, that I recall was more common back when I started this thread and was dosing higher and more often.
But overall, my bladder capacity seems solid right now. Like, normal. Less visits to the toilet than before, definitely.
So I guess for me, moderation is key. When I go raving like 3 or 4 weekends in a row, which I shouldn't be doing anyway, and this includes multiple bumps of K each time, well then that's bad for my bladder health. But I recover when reducing K use to normal, "year-round" levels, which is like once a month at most.
My saving grace is my current batch of K isn't that good anyway, either that or K is losing its magic for me. Like all drugs eventually do...
Will keep you posted.