Apple does not make certified Apple parts available to the independent repair marketplace.  Until recent this was not a problem as it was possible to obtain ‘factory overrun’ original Apple parts directly from China.  Apple has since increased the control on their supply chain in order to stem the flow of original parts to the independent repair marketplace.  At the same time, Apple started offering more reasonable priced iPhone 6 screen only replacements.   You can even send the device in for repairs using regular mail.  Independent repair can not compete with these practices.

For prices on screen repairs:

https://support.apple.com/en-au/iphone/repair/screen-damage

AppleCare+

Apple offers a protection plan called AppleCare+.  AppleCare+ is more like a protection plan than insurance. It extends the warranty and support period and covers against defects, battery issues, and more. It also provides coverage for up to two occurrences of accidental damage, with a service fee for each incident. Water immersion and most physical damage is covered under this protection plan.  Not covered by AppleCare+ are theft, loss, or any other incident where you can’t physically bring the phone to Apple for repair or replacement (broken or not).

Apple goods come with guarantees that cannot be excluded under Australian consumer law. In Australia, you are entitled to a replacement or refund for a major failure and compensation for any other reasonably foreseeable loss or damage. You are also entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality and the failure does not amount to a major failure.

https://www.apple.com/au/legal/statutory-warranty/

Independent repair marketplace

Third party independent repair can perform basic and intricate repairs for devices that do not pass inspection where the customer would normally be invited to purchase a refurbished device at a reduced cost.  Here is a list of the most common aftermarket repairs:

1. Screen repair

In situations where the body of the device is dented, third party independent repair can still perform screen repairs whereas Apple will most likely offer the device to be replaced at a cost.

2. Error 53

With a recent software update, as part of the update process the iPhone 6 will check for a signal from the original fingerprint sensor that is coded to the logic board, and if it does not detect that signal the phone will brick with error 53.  It is a simple check “hello fingerprint sensor xyz, are you there?” if “yes I am here” is not received—the phone bricks.

Aftermarket home buttons have no fingerprint sensor at all.  They are just home buttons.   You need to be aware of the importance of preserving the original home button at screen change. Fortunately, Apple has changed this behaviour in a recent software update.

https://support.apple.com/en-au/HT205628

3. Audio jack

Not being able to listen to music, podcasts, and other kinds of audio is a problem. Not only that, if your iPhone thinks headphones are plugged in when they aren’t, a broken headphone jack can affect sound sent through the speaker too. Other symptoms could include crackling or audio cutting in and out sporadically.

Note: The headphone jack in the iPhone 5s is actually part of the dock assembly. This means you’ll be replacing the entire dock in order to restore functionality.

4. Charging port

If your iPhone or iPad device isn’t charging anymore, it’s possible that either liquid came into contact with your charge port, or one of the pins are broken. Other symptoms of a bad dock connector can include iTunes not recognizing your device when it’s plugged into the computer.

5. Battery replacement

Smartphone battery performance always takes a hit over time as charge cycles take their toll. Sometimes things go wrong though, and an iPhone’s battery life starts going south much sooner than expected.  If your iPhone 6 is under warranty or covered by an AppleCare protection plan, Apple will run some tests and likely replace your battery for free. If you’ve somehow voided your warranty or the battery is excluded from warranty, you may have to visit an independent repair shop to replace a faulty battery.