Hi Ivy, welcome to the Forums!
What is the reason you need a new phone every year? Do you wear it out that quickly?
Unfortunately, even if you are happy with a handset, mobile phones are designed to fail relatively quickly - planned obsolescence. But you should be able to get a good few years out of them if you're lucky, barring any unforeseen accidents. My old HTC Desire is still going strong after almost three years (although I also have a new handset and now use both!)
One of the best ways to handle new phone purchases is to try and wait until the biggest leaps are made, like when new flagship models come out or new OS releases come stock with the phone. It's also good to buy devices that have good reputations already, so you're not having endless software problems or hardware failure.