Since we lost the on-MacBook charging lights (RIP).*
Apple Watch: set watch on charger or tap watch screen to check status. Same for iPhone. Tap AirPods case to see charging light as well.
*Guess I’ve survived without this, but it was a bummer my first Mac without it.
Ooh, “Your Apple Watch is fully charged.” notification on iPhone, that’s nice too. (Can sometimes just charge while showering/etc. and not think about it though.)