Proper usage and maintenance of the MagSafe power adapter can substantially increase the life of the adapter.
While the MagSafe power adapter is designed to travel with your Mac notebook, some ways of using it can contribute to the fraying or breaking of cables. The MagSafe adapter, like any other metal wire or cable, is subject to becoming weak or brittle if repeatedly bent in the same spot. Follow these recommendations to reduce the likelihood of damaging the adapter.
Inspect your power adapter
The most important way to maintain adapter health is to regularly inspect the cables, connectors, and the adapter itself for any kinks, breaks, bends, or other damage. If you find any such damage, stop using the adapter.
Unwrap and handle the cable correctly
When unwrapping the cord from the adapter, be sure to support the weight of the adapter. If the connector is held and the weight of the adapter is used to unfurl the cable, the cable or the adapter itself could be damaged.
Excessive bends in the cable might damage the cable over time. The most likely points where excessive bending can occur are near the adapter brick, or the MagSafe connector itself. Keep some slack in the cable at these points to preserve the durability of the adapter. When you route the cable, aim for gentle curves instead of angles.
Use the three-prong power cable to extend reach
If you use the two-prong "duckhead" connector for your MagSafe adapter and you find that the cable barely reaches, switch to the longer three-prong, grounded connector to improve the reach of the cable and reduce strain.
Route the adapter cable
Mac notebooks have the MagSafe connector on the left side of the computer. With the T-style adapter, if you need the cable for the adapter run to the right side of the computer, run the cable around the back instead of under the computer.
When using the L-style adapter, never run the cable along the ports with the connector plugged in backwards as this makes it difficult to disconnect. Make sure there's plenty of slack on the connector side and that the connection isn't strained.
Always keep the area around the adapter and its cabling clear. Some items that come into contact with the cable could cause damage.
Disconnect and store the adapter
Properly disconnecting the MagSafe connector from the computer can prolong the life of the adapter. Disconnect using the connector itself instead of the cord, as discussed in this article about using and maintaining your Apple MagSafe Adapter.
The "wings" on the adapter allow the cable to be stored with the adapter using a very small footprint. Note that improper wrapping of the cord on these wings can cause issues similar to bending the cable. When wrapping up the cabling, be sure there isn't additional strain on the cable where it connects to the adapter brick. Wrap the cable loosely to avoid creating undue stress or harsh angles with the adapter.
If you use your Mac regularly in the same locations, consider getting an adapter for each location. Having a dedicated power source in each location limits the need to set up and store the adapter frequently and helps avoid damage.
Whether or not your adapter is still covered under warranty, you can take it to an Apple-Authorized Service Provider or Apple Retail Store for evaluation. You don't need to take your Mac, but you should bring your computer's serial number.
The Apple-Authorized Service Provider or Apple Retail Store will provide you with your service options after assessing your adapter. Make a reservation at the Genius Bar before visiting your local Apple Retail Store. (Not available in all countries and regions.)
For more information on properly disconnecting the MagSafe power adapter, see Using and maintaining your Apple MagSafe Adapter.