I've had my S9 excatly a year, from when it was first launched in the UK.
I love taking photos, I've taken some fantastic photos with my S9 over the last year, really good quality thanks to the S9's superior camera.
The S10 comes with 5 cameras! And is a further upgrade on the S9's already very good camera.
That's how I justify to myself that the S10 is worth upgrading to, even though my S9 is only a year old and works perfectly well.