You can use Kore 2.0 Elite without pairing it with a phone. It will store data until its memory is full, at which point you will need to clear old data. Otherwise, new data cannot be recorded.
When you pair Kore 2.0 Elite with the mobile app, the app will remind you once every 30 days to clear data. Current reminder text is:
(We suggest freeing up watch memory every 30 days. All data has been copied to your account. No data will be lost.)