The smartphone world is a harsh, fickle mistress.
That small sensible voice in the distant nether regions of your brain will be whispering to you, urging you to be sensible and hold on to your 5s for another year, and we can't blame it.
The 5s is still a fantastic device, and with iOS 8 landing on it soon, your sensible inner voice makes a very valid point.
Still, it would be rude not to look at a few reasons to upgrade to the shiny new iPhone 6, wouldn't it?
READ MORE: Apple iPhone 6 hands-on review
1. It has a bigger screen
Unlike the 5.5in iPhone 6 Plus, the 4.7in display of the iPhone 6 should still be manageable for most people, although we're not going to lie and say that easy one-handed use will be possible for everyone. Just ask Craig Grannell.
Android users have had the luxury of 4in+ smartphones for what seems like forever, so the Apple faithful might be scared off by a larger screen.
Try it out, however, and you'll be rewarded with a better browsing and gaming experience, albeit at the expense of being able to easily reach all corners of the display with a single thumb.
If 4.7in really does feel too big for your hands then that could very well be a deal breaker. But if you're willing to adjust - and trust us, after a day or so you'll get used to it - then that extra space will definitely be worth it.
2. It has more power
The iPhone 5s is hardly a slouch, but Apple's new quad-core A8 processor is a beast. It's faster, and offers more pixel-pushing power thanks to an improved graphics processor, all of which promises to deliver the best-looking iOS games we've ever seen.
No, it's not like the current slew of iOS games look hideous, but you might find that releases later down the line stretch the iPhone 5s' silicon a little.
The new M8 motion co-processor can also now automatically detect if you're cycling or walking, and you can track how many flights of stairs you've climbed too, thanks to elevation measuring.
If you're a spec fiend after the best numbers or an avid gamer, then switching to the iPhone 6 is a no-brainer, but otherwise there's probably not enough reason to upgrade based on power alone.