Inclusion Criteria:  previous diagnosis of symptomatic kidney stone in past 5 yrs 24-hr urine volume <= 2.0 L/day, age 18 or older, own iOS or Android smartphone, proficient in English language, capable of providing informed consent, and willing to wear a Fitbit smartwatch daily for 1 year.  Exclusion Criteria:  previous diagnosis with cystine stone, pregnant or planning to become pregnant in the next 12 months, concurrently participating in another study involving fluid intake or diet, plan to have surgery or relocate outside the area within the next year co-morbidities that preclude high fluid intake, conditions with high fluid losses (Congestive heart failure, bariatric surgery, GI tract ostomy, short gut syndrome, chronic diarrhea including patients with ulcerative colitis/Crohn's disease, hyponatremia), or conditions that preclude ability to collect 24 hour urine (severe urinary incontinence), active medical treatments that would impair protocol compliance, chronic use of lithium, or psychiatric conditions impairing compliance with the study protocol.