I get cystitis probably two /three /four times a year. I have diverticula in my bladder.
Coffee is a bladder irritant so a definite no.
I'm not convinced that for me drinking more than thirst prompts me to, makes any difference to the frequency / urgency / pain, or to how long it takes to clear.
Sometimes I have symptoms with no causal organisms, and no one wants to take unnecessary antibiotics (because then they'd have thrush, too, or is that just me?), so I'll always give it a couple of days of management before I head to, in this case, the out of hours GP service at the hospital.
That's a fun way to spend time at Christmas. And a rant for elsewhere. The GP expressed surprise that my usual GP didn't have me on permanent low - dose antibiotics, or a repeat prescription for a course of blitzers, to save me bothering them when we all know exactly what's going on. Why indeed.