Days Since Last Sync is a count-up of time (days) since you last synced your device with the DermapenWorld app.
DermapenWorld devices require a sync with the DermapenWorld app every 90 days. By using the Dp DOCK your device will sync automatically with the DermapenWorld app every time you place the device on it. If you do not have a DP DOCK, you manually need to perform the sync on your device and app every 90 days.
