I've scoured the Internet, and read many versions of this question on this forum and others alike, but they're not really helping me decide. As many of you may know, BestBuy has all their Macbooks on sale this weekend, even more so if you're a student (another $150 off), and so it turns out that they're cheaper than if I bought from Apple directly (about $50 cheaper overall to be exact, and I don't have to offload the $100 App Store giftcard I'd get as part of Apple's "back to school" promo, which starts in July. I really have no desire for anything in the App Store or on iTunes. Anyway, the only issue is, I *was* going to get the 13" rMBP with 256GB flash storage and 16GB of RAM, I was going to max out the RAM (for a whopping $180 more). That was the plan. Then I saw these deals on BestBuy (which of course lack "customized" Macbooks, the only one with 16GB is about $1,000 more, the 15.4" model), and started really asking myself, "do I really NEED 16GB of RAM?". I was looking at the numbers in Activity Monitor for Memory, and I've read not to trust them, among other things... But some clarification would be nice. I did a sort of "stress test" for the RAM in my current 2012 MBP (with 8GB of RAM), by opening everything I'd have open on a typical day, from Coda (like three windows and a combined 20 or so files), to Chrome, to iTunes, to even a couple of Xcode windows... and then opened up Safari, FireFox (each with at least 5 tabs on various pages), Server, Transmit, Kaleidoscope, Numbers, Pages, Spotify, the App Store, DaisyDisk, Aperture, VLC, Messages, and at the time there was even a Windows 7 VM installing updates (I dedicate 2GB to it, but Activity Monitor showed it as using a mere 78MB while installing updates.. Anyway, as I was opening application after application, I noticed the "Memory Used" got to about 7.99GB (out of 8GB of course), and then from there the numbers on the right column (App Memory, File Cache, etc.) started shifting around. So it looks like OS X easily "maxes out" the RAM, but for nonessential stuff, and then when apps need the RAM, it is reallocated as necessary. Also, all the while, Swap remained at 0, for what that's worth... This isn't my first rodeo buying a Macbook, but it is the first Macbook where I can't upgrade the RAM later, so of course I'm hesitant to just "jump into" 8GB. I understand the idea of "future proofing", but that really has yet to be an issue for me. Historically I'd buy, say, a 32GB iPhone, you know, since I wouldn't be able to up it later, but I never used nearly that much space, not since my first iPod Touch six years ago. And so my 5s is 16GB and it suits my needs. So my thinking kind of is, while I want to get as much "runtime" out of this hefty purchase as possible, I'm not sure the RAM will be the "first to go". I mean, out of processor power, RAM, and SSD size, RAM is definitely the one I expect to limit me first, but that's if it ever does. Besides, the "standard" for Macbooks is still at 4GB, so I'm already upgrading the RAM a tier technically, even though that's what I currently have. Anyway, besides RAM and processor and SSD storage, I/O gets upgraded (ie. Thunderbolt 2), form factor gets upgraded (albeit not as often), battery life gets upgraded, Apple might even go for 4k tech in future Macbooks. The point is, even if I max out the RAM, I feel like I'll never really need it before I end up having to upgrade for *another* reason (a need for better battery life, or a better processor or something like that). So if I was to 100% decide on the 8GB model, this weekend would be *the* time to buy it. Not in July via Apple's "back to school" promo- now. But if I decide on 16GB, of course the prime opportunity is in a month or so. The difference in cost between the 8GB from BestBuy now and the 16GB from Apple in a month is about $226 (and $100 of that is an App Store gift card), so when you put it that way, I'm hard-pressed to justify shelling out for that RAM. For what it's worth, I'm a Computer Science sophomore, though I don't expect my RAM usage to really go up as I take those computer classes (actually the sad truth is, they love Microsoft at my school, so I'd either be VMing Windows or just using school computers for said work, haven't decided yet)... But I'd be working with the likes of Visual Studio for at least a few classes. So while it may sound like I kind of answered my own question, your input, as well as more info on the numbers in Activity Monitor, would be greatly appreciated! Virtual Memory is sitting at about 11GB (how is that different from Swap?), but in Server, its showing the RAM usage at about 5GB while Activity Monitor shows it as 7.99GB.