I've had it for just over a week. The first 5 days and nights were great. Then on the sixth and seventh nights, the watch disconnected from the phone app as sleep mode started, losing those nights' data. The connection automatically reestablished on each of the mornings when sleep mode ended. On the eighth night, when I saw that it was happening again, I went through the protocol that popped up for troubleshooting the connection which involves removing the watch from the app and from my phone's Bluetooth list, and re-pairing as if the phone is new. That worked, and it stayed connected all night!
Last night, the ninth night, I went through the protocol again after it disconnected (and it took a number of tries, which was frustrating because I needed to have been asleep instead of mucking around with a watch), and it appeared to work. However, I saw upon waking in the morning that it disconnected after @40 minutes, losing most of the night's data.
Even if this protocol was reliable, I shouldn't have to be re-pairing the watch to my phone every night after sleep mode starts. Any suggestions?