Pretty Good

My Problem

Got my MacBook Air almost five years ago—the battery's capacity was getting pretty bad.

My Fix

Opened up the MacBook, cleaned out the huge amounts of dust, and replaced the battery. Strangely, the iFixit battery cable was slightly longer than the stock battery's cable. After a bit of bending to get the cable to line up, I got it to fit in the socket.

EDIT: A few months later. In System Report it's telling me to "Service Battery" even though I'm only on cycle count 81. Weird.

My Advice

Be patient, and try to bend the long replacement battery cable to form a loop. This will use up the excess cable and allow you to fit it into the socket on the board.