iPhone hardware is usually not the root cause of slowness. Apple spends aggressively on the quality of hardware. This ensures you a quick recovery from bad software.
All the apps on the Apple app store are thoroughly reviewed yet you may find some poor performing apps once in a while.
I have collected these generic tips that will work on any iOS device including iPhone iPad or iPod.
Simplest Thing First: Restart Your iPhone
You can shut down and restart your iPhone to see if things improve. Most people do not turn off their phone and it makes it sluggish after a few days. Restarting your iPhone once a week may be good for keeping it fresh.
You can try other approaches if a simple reboot does not help you.
Storage Cleanup: Remove/move Pictures and Videos
Most space on any phone is taken by pictures and videos. If you are running low on storage space pictures and videos can be moved to another computer or an external hard drive. This can make room for a lot of apps and will surely improve your iPhone speed.
You can use some apps that can automatically backup your photos to network storage or cloud. This way you can easily delete them when you are running low on space.
Uninstall Apps That You Don’t Use
The simplest thing to speed up your phone is to uninstall all unwanted apps. Many apps are rarely used on phone and you can always download them again when you need them.
Even if you had paid for these apps, the app store will not charge you again for deleting and re-downloading them.
Each app takes up storage capacity from your phone. You can go to the Settings app and see the storage used by each app.
At times, removing mostly used apps will also help save space. E.g. Gmail takes up a lot of space on phone. You can delete it and download it again. This reduces the storage used by the app quickly.
Shutdown Open Apps
When you press the Home button on an iPhone it sends the app to background. This may keep the app running while you are not really using it. You can double press and swipe up to kill all the unwanted apps on any iOS device.
Clear Safari Cookie and Data
This is generally a good practice for privacy as well. Many apps that are tracking the location and other data can access it while they are running in the background.
Safari stores website cookies and related data in its cache. This data keeps growing over and over. If you think space is too low you can consider deleting website cookies and other data from Safari cache. This may mainly save you space.
Reset To Factory Settings
iOS provides an easy way to recover your original factory settings of iPhone. This is helpful when your phone may have been infected by a malware or virus.
Factory reset makes you lose all the information on the phone, therefore, take a backup of all critical data on your phone before you reset your phone.
Restore From Backup
Update iOS: Sometimes It May Backfire
Many people may not agree with this however at times it helps to not upgrade. iOS upgrades right after the release of an iPhone are considered good for new iOS devices only.
There is a perception in the internet community that Apple intentionally introduces the slowness in older versions of iPhones to force users to upgrade to a new iPhone.
Many people fear that older version of iPhones may get slower by doing iOS update. I have noticed a lot of rumors about this in past and therefore recommend you proceed with caution.
If you are noticing that upgrading your iOS has slowed you down. You can factory reset your iPhone to get the original iOS version it shipped with. This may not be an easy route though since Apple intentionally makes it hard to downgrade.
Summary
I hope one of these techniques will help you speed up your iPhone. Did I miss anything in this article? Please share in your comments.