The larger version of the Apple Watch has better battery life
In addition to holding its big keynote to show off the new watch and MacBook, Apple updated its website with a ton of new information about the watch.
On its page about battery information, Apple writes that the 42mm-sized watch "typically experiences longer battery life" than the 38mm version, as blog 9to5Mac first spotted.
Apple notes that its tests were done with pre-production units, so it may not reflect the final version. But at the very least, it's probably pretty close.
In general, the Apple Watch should last for about 18 hours on a single charge, according to Apple. That's after 90 time checks, 90 notifications, 45 minutes of app use, and a 30-minute workout with music playback from the Apple Watch via Bluetooth over the course of 18 hours.
It's comforting to know the Apple Watch will last a full day, but it's also worth noting that this can vary depending on how you use the watch.