Optimal Injection Interval for Intra-Detrusor Botulinum Toxin

The goal of this clinical trial is to see if patients deciding their own follow up times can increase the effectiveness of botulinum toxin (BTX or "Botox") injection for overactive bladder (OAB). The main questions it aims to answer are:

* Does the time between repeat injections differ from the 6-month standard when it is based on patient symptoms alone? * Does symptom control or patient satisfaction change when patients control their own follow up times?

Participants will undergo standard botulinum toxin injection into the bladder for OAB treatment and will then be randomly assigned to follow up either at a standard 6-month interval or whenever they feel their symptoms return.