Why do my iPhone chargers always break and how can I avoid it?

I've went through probably at least eight chargers in the last few years and they always break. Those were all used to charge my iPhone 5c, now I have an iPhone 7 and my charger is breaking again. It only works if I angle the charger which probably will end up damaging my phone. I'm usually very gentle with my chargers and they all come either with my iPhone or from like Best Buy. I don't know how to stop them from always breaking. Any ideas?

Added (1). Why do my iPhone chargers always break and how can I avoid it?
(The charger I'm currently using that is breaking came with my iPhone 7 so it's definitely a legitimate Apple product)

So far, my best wire has been from Staples. It's lasted 2-3 times longer than all of my other ones.

I always get "This charger may not be compatible with your device" warning in my other wires, even though they're Apple Certified.

Its your phone thats the problem, not the charger

Because you pull its cable too hard that breaking inside the code or the plug joint. This simple trouble can be fixed by either replace the cable or the plug.

Those chargers are made that way so you would buy a new one every time they go kaput paying premium price. But there's a way you can avoid paying a dime after you buy this charger. It can charge any Android and any iPhone. I'm posting the link below.

Lightning to micro-USB Adapter ; https://www.amazon.com/...B00XXLMEZC

Pull on the plug, NOT the wire, and it don't break (will be less likely to anyway), don't wrap the cable around other things and do not twist the charger cable. If you wish to USE the phone while charging, get a LONGER cord.

As others say, just make sure you hold the plug by the hard plastic body and never by the wire or strain relief, while connecting or disconnecting the phone.

Also, do not pull the cable anywhere near tight while handling the phone while it's on charge; move the charger nearer you or you nearer the charger, so the cable always hangs loose.

Any cable that gets flexed hard in the same place regularly _will_ fail; that's just the way things are and not a fault in the cable.
Bend a paper clip back & forth a few times and it breaks, it does not mean it was faulty. Same thing, metal fatigue from excess flexing.

With numerous iphones and ipads in the family, we have only ever had one single cable fail and that was an "ipad 1" 30 pin one, on a tablet mostly used by a five year old. By the time it actually failed, several parts of the jacket were worn completely through.

Stop sitting on them

Apple actually makes their products fragile and disposable so they can roll in the dough. The trick to this is that you only use the charger when you have to, not all the time. And, NEVER bend the edges, even SLIGHTLY, they are designed so that doing this messes up the wiring.

Check it -- http://smart-technology.xyz/iphone-8-design-confirmed/