[Nexus 6  General] JulesJam:
I would and put in the description that the device was only turned on to test it, then list the date the warranty extends to. That is what people mostly care about - how long of a warranty the device has. You can check that here:

https://selfsolve.apple.com/agreementWarrantyDynamic.do

It really is a good idea to test the device before you ship it out anyhow because it is not unheard of for people to get brand new iPhones that are defective. If you test that the phone can make calls, test the speakers, bluetooth and wifi, examine the screen for dead pixels (at least as best you can with the screen protector on) and all functions/looks good, you are more likely not have gotten a defective device. Even if the buyer can get a replacement device from Apple under warranty, some will want you to accept the device as a return which is a hassle so better to test it out IMO.

The only potential issue is if you don't have a lightning cable to charge the device, then you have to open and unwrap the cable to charge it. I have Apple cables and chargers so I don't have to do that.

And of course, don't set the phone up with an Apple ID, don't put in a passcode, don't do touch ID and then factory reset when you are done testing. You actually can set up all of that if you really wanted to test out everything on the phone, but you have to know how to undo all of that if you do so that you don't send out an iCloud locked device by mistake. It's just easier if the device was never associated with your Apple ID.

It really varies by what else is listed at the time you list yours. If there are a bunch of Space Grays for sale, then the Silver and Gold will command higher prices due to lower supply. And vice versa if there are more Silver and Gold, then Space Gray will command a higher price.

So check the swappa site to figure out what is currently listed and what the phones are selling for. I typically go with the SG models b/c I don't like the white faces (which has nothing at all to do with resale value; it is just easier for me not to have to worry about color) but sometimes the white faced phones sell for more. It really varies based on what else is listed and who is buying at the time you are selling yours.

---------- Post added at 06:59 PM ---------- Previous post was at 06:51 PM ----------

Also, remember that you need the device to show up in your device history for the gift card purposes, so after you have tested it and popped the SIM card in your N6, double check that the iPhone is in the device history. To do that you click on activate or switch a device, then select that you are activating a device that has been on your account before and you should be able to select the iPhone from the drop down menu. If you can, then the device shows as having been active on your account in the Verizon system. You don't have to actually reactivate the iPhone, just check that it appears in the drop down menu.

Again, it may be possible to get the gift card even if you don't activate the phone on your line, idk for sure, but when I ordered through the Comcast link, I had to call to get the gift card sent out and they checked to see if I had activated the device or not on my account. So that is what I am basing this on - my past experience trying to get the gift card.