I'm tied into a 2 year contract at the moment, but will see what offers are on when i'm able to upgrade free of charge. The wife is into the third year of having her phone and as it still works she's happy with it.
I have Samsung Note 2. I've paid full price as it's more cost effective that signing a contract for two years. At least in UK.
Still working well and don't see any good reason to change for anything else. I use my phone mostly for Internet browsing and very few phones can compete with note2.
I have some friends who change their phones every 6 months because they're rich or because their work give them a lot of budget to buy new stuff.
I personally don't have this money and this interest in changing my smartphone because I really don't need to. I will use mine until it's totally broken!