Hey Marc - we do pull from the phone you're paired with, and update every time you sync! You SHOULD (and I'll have to check with engineering to make sure I'm not lying) only have to set the time and date the first time you set up your tracker, and if the battery completely goes flat you'll likely need to set it again. Are you seeing time drift/incorrect time even if you're syncing regularly?
Marc Nagy
Instead of entering time/date, especially for people who live in time zones that have daylight savings (where the time switches twice a year), could the Striiv not just pull the current date/time from the device it's paired with?