If you're an Apple iPhone user you'd might have realised that after setting an alarm, your snooze time is set to exactly 9 minutes. If you were previously an Android user, you'd probably be frustrated as Android allowed a user to set whatever snooze time they want on their native alarm app.
But there is actually a reason behind the 9 minutes snooze time on the iPhone.
When Apple designed their clock systems in their devices, they programmed it according to traditional methods found in analogue clocks. For centuries, analogue clockmakers had their clocks set to exactly 9 minutes past ten in all their advertisements and display units which allowed the watch maker's logo to be perfectly visible, and to give a positive "smiling face" appearance.
Apple does the exact same thing with the adverts of their Apple Watch which is also set to 9 minutes past 10.
According to Apple, having a snooze time of 9 minutes exactly, allows the body further rest, but not allow for it to fall into a deeper sleep, which causes you to be more drowsy when you wake up after the snooze time.
However, a more convincing factor is that it is far easier to program a single-digit snooze time into their operating systems as opposed to a double-digit number.
Apple doesn't allow iPhone users to change the snooze time duration, but that's a simple fix with a third party clock app.
Take a look at the video below by the YouTube channel, Apple Explained, on Why The iPhone Snooze Time Is 9 Minutes.