Apple

Keep them as backups. Then sell them in 50 years when they’re antique.

Give them away to little kids

I use mine for security cameras, but never use it for longer than 4 hours - depends on the model I guess.

Repurpose them for specific tasks. As an SE3 owner, I wouldn't mind that 7+ to use as a wifi streaming device.

If you want to do something fun with it jailbreak it.

I'm here from the other side (username checks out), but I have a bunch of Pixels, and usually use all of them. My 8 pro is my daily driver, old 7 pro is my secondary for now (I treat it like you would a tablet I guess) and will eventually be passed to a family member. My 6 pro and 5 are in use by family members, and they'll be upgraded once they stop getting security updates. My 3 is used for playing around with LineageOS. My original pixel is a GPhotos backup slave. My original original pixel's motherboard died, and I miss the Nexus 6p I traded in for it...

I use one for porn consumption. The other I use as a travel phone since the 15s don’t have SIM cards anymore.

Should of sold them when they were worth something

Sell one to me?

I use my X as navigator in the car.

Can I buy the 7 plus off of you? But I would say use them as an iPod or security camera monitors

I have iPhone 6 thats connected to a BT speaker for my noise machine at night

You can put other SIM cards in them, keep them connected to power and set them to share calls / texts with your main iPhone. This lets you have 3+ numbers on your main iPhone.

Jail break em

Use it when your phone is stolen.

Sent from iPhone 7

You could sell them for some extra cash. You can use them for music or as a back up phone

You could try jailbreaking them and play around with customization and theming.

I keep mine around as a backup. So easy to flash your last backup onto it and use it between phones, if you lose or break your current one.

I use my 4s for verification codes whenever I get a new phone

Resell

Sell? Save one as a backup phone?

I used a 3GS when I had a 5s as a landline phone (voip)