Hi @scottsweb,
Yes, I recommend calling Spark.syncTime() at least once a day. Otherwise the local clock drifts up to about +/- 10 seconds per day on my core. I don’t think calling it more that once an hour is beneficial. If you need more exact time, you can check out my older NTP-based Spark Time library, but it consumes more resources and doesn’t current work with TimeAlarms (but that would be easy to fix).
It would probably be bad for the Spark cloud if we all called syncTime() at the same time at midnight GMT or something, so you probably want to call it based on relative time from when the core powered up.