After about 6 years with my white late 2009 macbook, I've decided that it's finally time for me to splurge and buy a new laptop. I'm a college student on a budget, so I'm trying not to spend too much money. After doing some research, I've come down to two options. The first option is to buy a refurbished 2015 macbook air, and the other is to buy a used 2013 15" rMBP my friend is selling. The rMBP would only be about $200 more expensive, and it comes with significant increases in CPU and GPU. It's also in great condition. However my main concern is longevity, as ideally this new computer would last me another 5-6 years. Are the rMBPs known to last a long time? Should I go with a better computer that is already 2.5 years old or just get a newer one with less power? Any advice is appreciated!