If you often get lost in the moment and forget where the time went, your Apple Watch can chime on the hour, every hour. It’s a reliable way to snap yourself out of it and get some water, take a walk, and otherwise keep yourself on track.
Enable Settings > Clock > Chimes on your Apple Watch, then pick between Birds and Bells chimes. Seriously, those are your only two options, even in the upcoming watchOS 8. Scroll down a little further, and there’s even an option to speak the time on every hour, even if Silent Mode is enabled (careful with that one).