Apple's new 13-inch MacBook Pro with Retina display offers a number of upgrades over the older version, including a thinner and lighter design and of course that ultra-high resolution display. But as iFixit's teardown of the new computer shows, these upgraded features come at a significant cost of upgradability and repairability. As with the 15-inch MacBook Pro with Retina display released earlier this year, the 13-inch version features proprietary SSD storage and RAM modules that are not easily replaceable or upgradable (or in the case of the RAM, not upgradable at all).

This doesn't come as a huge surprise — Apple has been progressively making its computers less and less user serviceable and upgradable ever since the original MacBook Air was released in 2008. And the company's line of iPods, iPhones, and iPads have never had parts that were accessible to users.

But the 13-inch MacBook Pro is Apple's most popular computer, and the Retina version will likely be very popular as well, despite its high price tag. That means that a lot of users that may have been accustomed to upgrading their RAM or storage over the lifespan of their older computers may be surprised that it's not possible to do so with the new Retina version. In light of that, a buyer's best bet might be to opt for the larger SSD storage choices when they purchase the computer. As for RAM, unfortunately, Apple is only offering one option on the 13-inch MacBook Pro with Retina display — 8GB — so you have to either be happy with that or choose a different computer. Those that plan on upgrading their components over the life of their computer may be better served by the original 13-inch MacBook Pro, which is still available and costs about $500 less than the Retina version.