How to put your old iPhone to use after you bought the new iPhone XS
Okay, we probably wouldn't be responsible adults if we didn't mention that you can give your old iPhone to your kids or a charity. We definitely wouldn't be fiscally sensible if we failed to point out that you can get a little trade-in value on your old device. Now that's out of the way, though, here's how you can make that phone do a brand new job just for you.
Actually, make that many, many new jobs. Each of which is free, comes with a subscription you use elsewhere, or is extremely low cost.
This is a computer you've got here, this is a miracle of technology and the only difference between your old iPhone and your new is that one has a SIM card in it. There are limits: the older the phone, the harder it is to get software that runs on it. So you need to know both what iOS version an app needs and what the latest iOS is that you can run on your phone.