Non-muscle-invasive bladder cancer (NMIBC) is usually treated with surgery to remove the tumor (transurethral resection of bladder tumor, or TURBT), often followed by bladder-instilled medications to reduce the chance of the cancer coming back. Even with this treatment, high-grade NMIBC can return or progress, so patients need regular check-ups, usually with cystoscopy (a camera examination of the bladder) and urine cytology. Cystoscopy is effective but invasive, can cause discomfort, and carries risks such as infection and bleeding. This makes follow-up costly and sometimes burdensome for patients. This study is testing whether a urine tumor DNA (utDNA) test - a type of liquid biopsy that detects cancer-related DNA changes in urine - can help guide the timing of cystoscopy for people with high-risk or very high-risk NMIBC. utDNA testing is non-invasive and has shown high accuracy in detecting bladder cancer, sometimes spotting signs of recurrence earlier than standard methods. By combining utDNA testing with cystoscopy, we hope to safely reduce the number of unnecessary cystoscopies without missing cancer recurrences. The study will evaluate whether this approach can make bladder cancer follow-up more comfortable, more precise, and more efficient.