I have read a lot of posts about the need or advisability of buying a new Macbook Pro with 8 GB or 16 Gb of RAM, and reading many different opinions. Obviously everyone's needs are different, but my interest was in the idea of "future-proofing". So I decided to see how well future proofing worked in the past. So I checked out the dates each version of OS X appeared and the minimum and recommended RAM for each one. Graphing these up showed some interesting facts: The graphs are exponential (i.e. they plot as straight lines with the Gb axis shown as logarithmic), with RAM doubling about every 2.5 years. The gap between "Recommended" and "minimum" is also about 2.5 years (because the recommended is generally double the minimum). Thus, if you want to get 5 years life out of your Macbook Pro, you need to get about double the recommended RAM or 4 times the minimum. However these conclusions come with a big proviso - that you want to keep upgrading your OS whenever a new version is released (and presumably upgrade your other software too). If you are willing to work within the capabilities of the OS and software you use when you buy your Macbook Pro, then it will become unusable much more slowly, but eventually it will be impossible. This is for several reasons: Most of us connect to the internet, and as time goes on, websites, video formats, etc, upgrade their requirements, and eventually an old OS and browser cannot cope. Likewise, most of us receive emails from friends with attachments, and gradually these attachments cannot be opened using an old OS and the software that goes with it. (We have been using an old eMac with 640 Mb RAM running Tiger for almost 10 years. It still works, allows us to use the internet and emails, but now it cannot play video or open lots of email attachments, and we cannot upgrade the relevant software because the Mac can't cope with it.) So we can draw another approximate conclusion from my graph - if you are willing to stay with the same OS, you'll probably get a maximum of about 7 years out of your Mac if you start with the recommended RAM, and about 9 years if you double the recommended RAM - if other things don't fall down in the meantime. Applying this information from past performance to the future is doubtful. Perhaps the technology will change completely (not just quantitatively) in the future, perhaps RAM specs will hit some brick wall like CPU speed did, who knows? But the past is the only guide we have, so I hope this info might assist somebody. My conclusion in a nutshell: 1. If you're happy to upgrade to a new Mac every 2-3 years, get the recommended RAM for your usage. 2. If you want to keep upgrading the OS and want to replace your Mac every 5 years, buy 4x the minimum RAM or double the recommended RAM for your usage. 3. If you are happy to stay with the same OS and want to only upgrade to a new Mac when absolutely necessary, get double the minimum RAM at least. For most users therefore, 8 Gb will be fine if 2 GB is considered the minimum and 4 Gb is the recommended, but if you need more than 4 Gb now, get 16 Gb for the future.