The Skyn stores about 72 hours of data with continual use and the current data sampling frequency. After ~72 hours, the oldest data will begin to be overwritten if the Skyn is not paired with the Skyn app to transfer data to the web portal.
The best practice for using Skyn is to allow the Skyn app to continuously run in the background of the paired iOS device, but users should connect to the app at least once every 2 days.