While some of you might want to keep your current device around as a secondary phone, others might want to make some money or help out a family member.
It would be a good idea to start making some early plans for the device you plan on replacing this year or next.
Some of you might benefit from keeping it around for emergencies or to test Apple's iOS beta software. It's never a good idea to test betas on your primary device.
If you'd rather make some cash (or make someone extremely happy) you might start asking around to see if anyone might want your device when you upgrade.
If you don't know anyone personally you'll want to look into re-sale sites like Gazelle and Nextworth and lock in a good trade-in price ahead of the iPhone 8 release date.
Sketch out your plan now so that you aren't scrambling in the fall. If you time it right, you might be able to use some of the money you make to offset the cost of your new phone.