While hitting snooze won't help you much if you fall back asleep, it can help you wake up more gently. However, the default 9-minute snooze that the iPhone provides may be too long or too short for your preferences. If you tend to fall back asleep quickly, you might be better with a two-minute snooze.
In case you're wondering, old-school mechanical clocks had physical restraints that prevented them from using 10 minutes as the snooze time, so 9 minutes was set as the default since 11 minutes didn't seem punctual enough. Eventually, digital clocks continued the trend of 9-minute snoozes when dial clocks went out of style, and Apple most likely felt inclined to keep with tradition for its snooze time on iPhone alarms. If it's been working since the '50s, why change it?
However, if you tend not to get a good night's sleep or just fall asleep quickly when you activate the snooze button, you're more likely to fall back asleep into the beginning of a sleep cycle. This cycle encourages deep sleep, so when you're jolted back out of sleep by the snooze alarm, you're left feeling more tired than before. This is where a shorter snooze comes in handy, so it keeps you from falling back asleep and feeling more tired.
Unfortunately, I have some bad news. There is no way to change the snooze time for alarms in the Clock app. This has been asked for many times over since the invent of the iPhone, but it's not a big enough problem to break that 9-minute tradition, even if it's just letting us customize the time ourselves. However, there are some alternative options you can try to either get this functionality or simulate it.
If you're lucky enough to be jailbroken, you can use a jailbreak app such as Snooze ($0.99), by Julian Weiss, or Sleeper ($0.99), by Joshua Seltzer. However, since Cydia is non-existent right now in iOS 11, these jailbreak tweaks will only work if you're running iOS 7 or iOS 8–10, respectively.
If you're not jailbroken or don't want to jailbreak, then you have to get a little bit creative. In this tip, just time your other alarms around the 9-minute snooze. So, if you want snooze increments that are about 4 to 5 minutes, you could set one alarm for 6:00 a.m., as an example, then another for 6:04 a.m. — and that's it.
If you snooze those two alarms on time when they go off by either hitting "Snooze" on the lock screen, one of your volume buttons, or the Side button (the Home button will stop the alarm), then subsequent alarms will go off that you can snooze ... 6:09, 6:13, 6:18, 6:22, 6:27, 6:31, and so on.
Of course, this is a perfect world where you hit snooze right when the alarm goes off. If you wait a minute or two, it throws all of this off. If that sounds like something you would do, you can try the next option.
While you can't change the default snooze time in the Clock app for alarms, you can turn the snooze off. But that doesn't make any sense, right? Well, by turning off the snooze, you can make your own "snooze" buttons manually as new alarms.
In the Alarm tab of the Clock app, either add a new alarm with the "+" button or hit "Edit" and select the alarm you want to change. On the edit screen, make sure "Snooze" is disabled, then set all of your alarms 5 minutes apart (or whatever time you want). When you hit "Stop" on the lock screen or hit the Side or Home button (note the volume buttons will only silence the alarm, not stop it), it's effectively like hitting snooze since you have another alarm queued up as your snooze.
If you tend to hug your iPhone in the morning and just clench buttons whenever the alarm goes off to snooze it right away, you're not doing yourself any favors. To make alarms and snoozes more effective, keep your iPhone farther away than arm's length, that way you have to get up to stop or snooze the alarm.
Taking this one step further, you could enable LED flash alerts that will flicker bright lights in your face from the rear LED flash, which might wake you up even more. This can be done in the Settings app. Go to General –> Accessibility –> LED Flash for Alerts, then toggle it on. Keep in mind that this will provide flash alerts for more than just alarms, so you might want to disable "Flash on Silent" so you can at least set your iPhone to silent and not get flash alerts when you don't want them.
If none of these options sound good to you, then the best thing you can do is find another alarm app to use until Apple one day adds customizable snoozes to its Clock app (don't hold your breath). I checked out a ton of free alarm apps in the iOS App Store, and all of the below options let you customize the snooze time.
- Wake Alarm Clock: snooze for 5, 10, 15, or 20 minutes
- Sleep Cycle alarm clock: snooze for 1, 2, 3, 5, 7, 9, 10, 15, or 20 minutes
- Alarm Clock for Me: snooze from 1–60 minutes (in 1-minute increments)
- Loud Alarm Clock: snooze for 2, 5, 9, 10, 15, or 30 minutes
- Alarmy: snooze for 1, 3, 5, 10, 15, 20, 25, or 30 minutes
- Alarm Clock HD: snooze from 1–20, 25, 30, 45, or 60 minutes
These are just a few of the free options available in the iOS App Store. You could always browse for the one you like, then test it out to see if it has the right snooze customization options for you. The worst thing you could do is delete the app and try another one.
However, keep in mind that some (but not all) of these alarm apps may require you to keep your iPhone's screen on at night for best performance.