Seriously, I was reading this article wondering the same thing. Nanoseconds since X is a fairly unambiguous reference (relativity aside). Use this for any kin

Seriously, I was reading this article wondering the same thing. Nanoseconds since X is a fairly unambiguous reference (relativity aside). Use this for any kind of timestamp or recordkeeping. Convert to UTC (or EST, CST, etc.) as necessary for reference to the solar day. The only reason not to do this is because you have a million systems that are already running on UTC, and you don't want to do a massive leap second erasure to get back to TAI.