[throw0101a]

> 1 minute a month (upper bound) is hardly a deal breaker.

For a relative measure: if you're off by one minute when using a sextant, then you could be off by (IIRC) about 15 nautical miles.

So one should at least know the average drift of the time piece if it's being used for navigation, and it should be sync'd up with UTC/GMT regularly.

For regular day-to-day stuff, one minute is probably less dire.