In about 18 months of use, my Apple watch 7 battery life is down to 88 percent. One would surmise in about a year's time, it will drop below 80 percent. My iphone's battery typically didn't drop that fast, in fact iphone 14 pro, owned since September is still at 100 percent. I hope there is a methodology in place to replace the watch battery. Unless the watch 9 blows the doors off the watch 8, I have no desire to upgrade.