I had a adapter that was beheaded internally and would rotate 360° and obviously not work. I went to a Apple store trying to get a "their fault free recall replacement" as this one was newer (OEM MBP) than all my other ones. they told me they could swap it with a factory refurbished one for $45-50 or I could buy a new one for $80.
so what you think I did?
I bought a new one, the old one went onto my workbench and I Almost repaired it but broke the connector trying to get it apart. it went into a box, i moved, gathered some money ($15?) and ordered the replacement cable off of eBay.
and now for $95 I have a travel and home adapter.
the hardest part is actually opening the adapter although that can also be avoided if you don't mind doing a splice.
the biggest problem with Apple products is the cable they use, from Dock cables to lightning cables to MagSafe cables to iBook power adapters. they all have the same flaw, they are weak and wear out sooner so you have to buy a new one.
there is a GOOD reason why you don't find that style wire on your table lamp, in fact most twin lead zip cord is double insulated in countries with 250V AC to prevent the wires from fraying and shorting out or coming in contact with humans.
But somehow because it is DC it's perfectly acceptable.
I have also noticed that the folding prong adapters tend to wear out causing arcing, that's why I avoid using it and go for the 6 foot extension + a solid 3 Prong Grounded cord.
and it's not just Apple, I see the same problem on HP and Dell power adapters although the wire is a little bit better quality. and it doesn't stop there, 9V power supply for guitar pedals..... ( I got that last one for free because the original owner rather get a new one.) however the manufacturer change the wire style from coaxial to twin lead. I guess they learned their lesson and improve their product?? !!shocked face!! )
at least with the Apple adapter there is no "power adapter sense wire" as the circuitry is in the end, whereas HP and Dell have a 3 wire cord which has its own host of problems.