Nobody said external drives are not necessary. In fact they are, but the space you considered necessary could be debated, and $1500 of external storage for 6 computers is not too much. I back up two Macs with a single 1.5TB drive that was on special for $110 a few months back, and still have about a year of backups. True, I don't backup my downloads as they are easy to re-download anyway, the bottleneck being the internet connection itself. What could be discussed also is the amount of mobile external storage one needs. Having a blazing fast machine but having to haul an external drive at all times because internal is too small is a tradeoff not many would be willing to make.
Thankfully, with the optibay, it's not a trade-off many people have to make. Ultimately, the OP's mistake is not planning out how much local space they'd need or they underestimated that need.
The OP essentially has 750GB right now and misses having "mass amounts" of space...yet they're only talking about replacing the current SSD with a 1TB HDD? That's a gain, but hardly a massive amount more than their current setup and it will be massively slower. It's an "upgrade" that doesn't make sense. The OP would have 1.5TB of slow storage. I also have 1.5TB of storage, but I didn't have to make a compromise and forgo having an SSD.
Even with a SSD inside, I am not sure I would trade 16GB of RAM for a SSD: swapping must be much faster, but SSD is still slower than RAM.
Why would there be a trade between one or the other?
Nobody has said anything about giving up memory for SSD. 16GB is $125.
Given enough money in my pocket I would stick the 512GB SSD inside the MBP and switch the 500GB HDD in an enclosure. But I wouldn't gain speed when running virtual machines, and I find a bit wasteful to stick a SSD in an enclosure. So money and only average performance in some applications put me off.
You would absolutely gain speed in virtual machines if the VM image resides on the SSD. I don't know why you'd think otherwise. Booting the VM, launching apps within the VM, saving and restoring the VM state...these are all tasks whose speed is increased immensely when coupled with an SSD. You seem to have some misconceptions about what an SSD will help out with and since you haven't had any personal experience with them I find it odd that you would make assumptions about them that are the complete opposite of what people actually experience.
If you don't want to get rid of your optical drive or aren't understanding what people mean when they say "optibay" then I can understand why you're talking about external enclosures. The optibay replaces the optical drive with a 2nd 2.5" drive bay. Are you aware of this? The OP, as well as myself and countless others, have two drives INSIDE our MBPs. I have 1.5TB of internal storage; 512GB SSD and a 1TB HDD, all inside. I don't carry around an external enclosure to have the second drive and I don't take the 4TB external drive with me when I travel.
I do have a few, empty HDDs that are not connected, and looked for a cheap way to put them all online, and have failed to find one.
Depends on what you mean by "cheap" and "online." An empty 4-bay NAS can be had for relatively cheap, but they won't be the fastest in the world. I'm a big fan of Synology and their consumer 4-bay NAS, the DS413j, is $380. If you just want to toss the drives in an enclosure and connect them via USB3 then a 4-bay USB3 enclosure is under $100.
BTW what you show is not a 4TB NAS, but a 4TB external drive. That makes a whole difference in price / speed, although you surely share this drive from a dektop to the other machines.
I never said the 4TB was a NAS and I actually don't share it with anything. If you read back, I said it was a 4TB USB3 drive that I use for Time Machine backups (Specifically, for my cMBP that has 1.5TB of drives) and that I also have a 6.5TB NAS. Yes, I can, have and do use the NAS for Time Machine, and that is what my rMBP backs up to, but video editing on my cMBP and having it back up my projects over wifi doesn't work very well, especially given the Time Machine + NAS "bug" that results in random slow Time Machine backup speed. I couldn't risk my cMBP taking extra long to back data up so it has its own USB3 drive for backups and the 4TB USB3 drive was both inexpensive and takes care of that problem.
The bottom line is that nothing external to my Macs is "required" if someone wants to use an SSD. They need to evaluate their space needs and purchase accordingly.
The OP replacing two drives totaling 750GB with a slow 1TB HDD and keeping the 500GB just sounds like someone bored, period, that wants something to do. That much more space is not what I would consider to be substantial. I stick with my suggestion of getting a larger SSD and selling the small one, then determining if replacing the 500GB HDD is necessary and, if so, replacing it with a 1TB HDD will double that space.
I also think there is a difference between getting "bored" with the speed and getting used to it. Going back to an HDD-only config...I just can't imagine it. I would get frustrated with the slowness within minutes, not because it's truly slow but because it is simply much, much slower than an SSD.
Imagine living somewhere where there's traffic all the time and you can't get around very fast. Eventually you just get used to it and it's fine. Now imagine taking a nice, long vacation where there's no traffic and you can go anywhere you want in virtually no time. Eventually that becomes the new normal and you get used to it. What was "quick" is now "normal."
Now imagine going back home where there's traffic all the time. It would probably drive you nuts and you would always be wishing you never came back from that vacation.
Yes, SSDs really do make a HUGE difference in the user experience and can give new life to a Mac that someone might be thinking about getting rid of.
Until you've experienced an SSD yourself you really don't know what you're missing.
