If you bought a Macbook between October 2009 and today you may be facing dreaded “peel-butt” where the rubber flakes off of the bottom of the laptop. You can either bring your laptop into the Apple Store for free repair or they can send you a DIY kit. All you really have to do is unscrew a few screws and plop on the new one.
Apple has determined that under certain circumstances the rubber surface on some MacBooks may separate from the bottom case of the system. MacBooks shipped between October 2009 and April 2011 may experience this issue. Apple will replace the bottom case of any affected MacBook, free of charge, that exhibits the issue.
Best of all, they will issue a refund if you paid to have this fixed in the past two years.