If you do multiple tests in quick succession, the moisture on the sensor can skew your results. For this reason, we recommend leaving at least one hour between breath tests, and taking no more than 10 tests during a regular day.
When you're completing a food intolerance test, you will go through the Discovery section of the app and once you begin the test, the FoodMarble app will communicate to your device telling it to remain powered on with the sensors warmed up for the duration of the testing period. This is what allows you to take breath tests every 15 minutes during an intolerance test and get accurate results each time.
From a physiological point of view, it's also important to be mindful that a person's gas levels take time to recover after taking a breath test. If you're testing on two separate device, make sure to leave 10 minutes or so to pass before testing again.