I thought the removal of the headphone jack would be a huge inconvenience, but it's really not. First, the new phones -- including the brand new iPhone 8/8+ -- come with a set of earbuds that use the lightning connector in addition to the adapter (only useful if you have a nice set of headphones you still wish to use, like the Bose noise cancelling type).
If you're worried about lack of power, I HIGHLY recommend the Apple Smart Case ($99) for the smaller 6s/7/8 models. I've used mine for a year and never had lost power in the course of a day, even when using GPS for hours in the car and streaming music non-stop. And unlike the other options, like Mophie, it still has the Lightning connector port on it instead of the micro-USB.
Lastly, consider the newer AirPods for your headphones. There are wireless, charge in their case, and sound very good. You can use one at a time for phone calls and switch back & forth (use one while other charges, switch every 4-5 hours) for virtual non-stop use all day.
When you put all this together, it becomes insanely convenient and easy to manage.
- My Bose noise cancelling headphones stay in my laptop bag for air travel
- My Apple AirPods stay in my pocket and need to be recharged once every few days for normal calling or casual music when in Starbucks, restaurants, etc.
- My phone NEVER loses power before I head to bed because of the Smart Case, so I never really worry about finding a place to charge or hooking it up to my rental car
Hope this helps...if you really not into the facial feature on the iPhone X, just go with the new 8 and you'll still have these options available to you. Good luck!