Would you say 3 years is a good time to upgrade? I have a 4S with Sprint. My 2 yr. contract was fulfilled last year Nov. 2013. I need to get out of Sprint because they don't have similar non-contract plans like T-Mobile and ATT. I don't use data, except when in a WIFI zone. I pay $67 for talk and text basically (as I don't use the unlimited data offered by Sprint). T-Mobile and ATT offer Talk and Text anywhere from $25-$35. As you can see, it cuts my bill down to half. But to do this, I would need an unlocked iPhone 6 on launch day.
I'm basically paying Sprint $67/month, because I prefer to have the 6 over the 5S.