Want to make your phone like new? Does your phone die faster than it used to?
It sounds like it is time to replace your battery.
Batteries typically begin to die after two years of use. You can check your battery (on iPhone) by going to Settings>Battery>Battery Health> and then check the Maximum Capacity. If it is under 80% capacity, you may want to consider replacing your battery.
Replacing your battery can create the illusion of a brand new phone for half the cost and none of the hassle of transferring things over. I think it is a great way to make your phone last a little longer if you aren't quite ready to commit to a new phone, like the X or XS.