Mobility is the key feature of the emWave2. The emWave2 hand-held device is designed to be used with or without a computer.
You are not required to download data if you prefer not to. The emWave2 will record and store 18 hours of session data.
After that time it will simply stop recording any more sessions. It does not affect the operation of the device or warranty.
Remember, your ultimate goal is to be able to shift to high coherence at a moments notice without being connected to any equipment or software. Use of the emWave2 (or any HeartMath Technology) will teach your body what high coherence feels like and make that shift easy for you.