While the Retina MacBook Pro and MacBook Air systems do not have user-upgradable RAM, often other Mac systems Apple sells that do have this option are only shipped with a minimal amount of RAM, so you might find yourself needing to upgrade after a while.

Even if you are purchasing a new Mac, you might be considering purchasing one with a base level of RAM and then upgrading it later, to save money over choosing Apple’s relatively overpriced RAM upgrade options.

1. Avoid Apple RAM 

   While Apple sells RAM upgrades for its systems, both as CTO options and as standalone purchases, these are sometimes ridiculously overpriced. For example, as a CTO upgrade for its iMacs, Apple charges $200 to upgrade from the base 8GB to 16GB RAM. If you purchase this as a standalone upgrade, then you will be paying $400. In contrast, RAM with the same specifications from reputable manufacturers are available in online stores for around $130-160.

2. Get as much as you can 
   When upgrading your RAM, be sure to get as much as you have a budget for, or that your system can handle. While it may seem like overkill to put 32GB of RAM in an iMac, doing this will ensure RAM capacity will not be an issue as you upgrade to new versions of OS X and other software you use. Granted you can go overboard by putting 128GB of RAM in a Mac Pro, but for the most part you can put 16 to 32GB of RAM in a system, and then be well off.If you are purchasing a new Mac that does not have user-upgradable RAM, then I recommend you bite the bullet and go for the maximum amount of RAM that Apple offers as a CTO option.
3. Test it thoroughly

   Regardless of whether you have expensive RAM or the cheapest stuff you can find, be sure to test it thoroughly. While some companies do a good job in testing their RAM, you will only benefit from running your own tests. To do this on your Mac, you can use a third-party tool like Memtest or Rember, but will likely test more thoroughly by using Apple’s Hardware Test suite that is included with every Mac. For best results, take the time to run as many of these tests as you can.Be sure to regularly test your RAM, at a rate of about a couple of times per year. While RAM can last for decades without problems, sometimes odd manufacturing defects can cause good RAM to go bad after a few months, or a few years, or after exposure to extreme environments.

4. Keep old receipts 

   For any RAM upgrade purchase, be sure to keep your receipts and packaging. Most RAM companies offer lifetime warranties on their RAM, and will replace it if it goes bad. However, in most cases you will need to have your original proof of purchase.

5. Keep your old RAM 

   Finally, while many companies offer RAM buy-back programs and will give you about $10-20 for an old pair of 2GB RAM modules, if your new RAM does go bad and needs to be replaced, then you will have to wait for your replacement to come in. Even though the old RAM might not be of adequate capacity for your needs, you can at least use it to get by, and you might find this safety net worth every penny of the trade-in price for your old RAM.

By following these suggestions, you will spend less on configuring your Mac with the RAM you need, be sure your upgrade is in working order, and then be prepared to handle any snafus with your upgrade, should they happen.