My iPhone 6 was just getting tired.... Battery life was short and the lightning connector was getting intermittent. Sometime, after supposedly charging overnight, I would (not) wake up to a dead phone. The normal removal of navel lint from the connector followed by cleaning with a little contact cleaner no longer worked. Since "to repair in noble and to replace is expensive," I had to go for it. It was a little scary since I am 71 with not too great eyesight and a less than a totally steady hand, but I had to give it a go!
I ordered my parts from iFixit and waited...and waited....and waited... Wups,!I forgot to press last "enter" button, thus no order! I "reordered" -- about $60 for parts, tools, and taxes -- and all showed showed up ASAP. Repair took about 4 hours, including about an hour struggling with the tinniest co-ax antenna connector I have ever encountered. (see below)
Phone worked immediately - good long battery life and totally reliable lightning connector. 100% success, I would say. Old guys rule!
The coaxial connector for antenna cable is extremely difficult to reconnect. It must be properly aligned with it's socket and quite a bit if pressure must be applied to get it to snap in. The alignment is done entirely by feel as one cannot see the receiving socket while the plug if over it.
It took me over an hour of trying to get the new connector to seat. I actually reconnected to old connector (attached to the broken assembly being replaced) several times, just to make sure I hadn't damaged the receiving socket. Although the old connector would reseat easily, new one fought me every step of the way.
This connector snaps together much like a clothing snap. I think the one supplied with the new assemble slightly different in size from the old one, perhaps made that way to assure a tight and permanent fit. One thing is certain - once seated the connector will not fall out.
One more piece of advice. Before you begin the phone disassembly, find a parts container with at least half dozen small bins. Keep the screws and parts associated with each disassembly step in a separate bin. If you make the mistake of mixing all these flea sized (but all slightly different) screws together, you will have a difficult time figuring out which screw to use in each situation.