My Apple Watch 3 cellular lasted exactly 45 min with Spotify steaming into a pair of AirPods with the running app (GPS). Not exactly a practical solution for any kind of workout. I am not going to wear two watches; might as well take the phone with me.
Then there’s something wrong with your watch (if you started the run at 100% battery). I can easily do a 2hr run (w/GPS on obviously) + Apple Radio + AirPods. Sure, by the end of that run there’s maybe 10-15% but for me it’s just habit to throw it on the charger just like the phone at night. Inversely, I can wear it all day and still have plenty of battery for a 1-1.5hr run at the end of the day.
I have to admit, I was never a “music runner.” But these AirPods are a game changer (only in one ear of course!). The ability to receive pages/calls while ‘on call’ is also very important to me. So I’ll accept the disadvantages of the Apple Watch as a true running watch, because I don’t think there’s anything else that can offer me phone calls on my wrist, streaming (not stored) music to a compact bluetooth earpiece, and a does a decent job at tracking pace, HR and distance.