Yes, if you can accept the precision loss (you probably can) it's fine to ignore leap seconds, so only DST matters. Or time zones, if you're not using UTC, GPS,

Yes, if you can accept the precision loss (you probably can) it's fine to ignore leap seconds, so only DST matters. Or time zones, if you're not using UTC, GPS, or TAI. But I just got done writing a reference clock driver for the Chrony NTP server/client for a GPS module which outputs GPS time. But Chrony needs samples in UTC, so I did have to care about leap seconds to make that particular GPS source usable. And I had to add a way to update the leap seconds offset when a new leap second will be scheduled. Thankfully I had no need to convert differences between wildly different timestamps to sub-second precision.