My 'recent' history has been SE t610, SE K750i, Samsung Wave, Samsung Galaxy S - so not very often
A few reasons for that.
Wife, guilt and contentment. I love gadgets so left to my own devices (literally) I'd probably have a Note 3 or HTC One now.
My next phone will be SIM free and, at this stage, looks like it'll be the Nexus 5. As I've rooted and put vanilla Android 4.2.2 on my Galaxy S, it's been like having a new phone and it's still running very well. But now screens are larger and of a higher definition, I'm finally being tempted by the hardware improvements as they are within my ceiling cost of around £300-£350.
The Nexus line aside, buying last year's flagship phones is really worth considering. That's how I got my Galaxy S as it dropped temporarily to a £20/month contract when the S2 was announced. At the time, that was a good deal and justified the contract - and I've got nearly three years out of it and for the last year I have been on a £7.50 SIM only and, as a result, have saved quite a bit of cash.
Buying the latest and greatest comes at a premium whereas last year's models are still extremely capable devices indeed. The only thing that put me off the S3 was its build else I think I'd have bought one of them.
£35-£50+ a month for cutting edge devices is something I can't justify, sadly. That's crazy money when you do the sums especially if most of the tasks you undertake are performed more than adequately by 2012 devices. The only person I'm looking to impress is me, so I don't feel pressured to upgrade.