That’s what I’m planning to do. Just get a contract for 5-10 quid a month. And when the phone dies, I’ll just get a new one. The plan does involve forking our for a new phone but over the course of 2-3 years it will work out a lot cheaper especially if the current IPhone lasts for another year.
I've an IPhone 5 - nearly 4 years old and a sim only deal. I'll get a new phone once the apps I like using no longer work with IOS 10 - I reckon that will be a good 18 - 24 months yet, I think it's ridiculous how people buy new phones after 2 years.
We are a sim-only family (we've always bought unlocked iphones) and pay £7 - £10 each. There are plenty of one month notice deals around (you can get your phone unlocked once it is out of contract). I would imagine you would get at least another year of use out of your 5C.
We ran an iphone 4S for a good 5 years (did get a new battery) before we found we couldn't run all the apps we needed. I replaced it with a refurbished 6S after the latest batch of iphones came out.
I've been very happy using Quickmobilefix (bought a 5C for DD and my 6S from them).