While the Apple Watch does have up to 18 hours of battery life each day on a full charge, your results will vary depending on how often you use it and what you're actually doing with it. If your Apple Watch isn't lasting all day long, we've got some battery-saving tips you can try out. Of course, you shouldn't use all of these tips, lest you render your Watch mostly unusable, but you should figure out which ones make the most sense for you and your daily usage. Tip #1: Disable Unnecessary Not...