And what's the lifespan of these supposed to be?  
 
 

If you have never had an SSD before, they have a specific set of "caretaking" required which is summed up pretty well here (http://blog.tune-up.com/tips-and-tricks/four-steps-to-optimize-your-ssd/)
 
I have had mine for 2 1/2 years as the OS/Program drive and had it BSOD off and on, but not crash. As the drivers for it became stable it has run smoothly. From my understanding, they do not "crash" in the manner of a magnetic HDD (i.e. catastrophic failure), but the memory cells will degrade over time (they function similar to a massive chunk of RAM). As they degrade, they effectively would become "smaller capacity."
 
When I did research before purchasing mine, the predicted life-span several years, so would meet the same period as I intended to use the machine.
 
If you have never owned one, be sure to research thoroughly, and be sure you get a SATA III (6 Gb/sec) SSD and have SATA III support on your motherboard. An SSD using SATA II only is a waste of money (you won't see "lightning quick" speed out of it).
 
 

I have had numerous SSDs had lots of issues with the first 2 (trim and other issues)
if you are buying one today things are much better than they used to be
 

Basically I'm only concerned with reliability as compared to the magnetic(?) kinds.  Thinking they had no moving parts gave me the impression they would last much longer and be much more reliable.  Not that my files are priceless, certain items I would not like to lose, and therefore have a pile of external drives I leave unplugged, unless I'm backing up to them.  My computer always has a backup drive connected, so I'm making backups to that on a more regular basis (then to my others I leave unplugged).  I've lost several externals over the years, so I never trust a single backup anymore.
 
BTW, I'm also under the impression that plugging these other hard drives in and using as needed, is OK and might actually extend their lifespan, as long as I DO use them now and then.....correct?

mettelus
If you have never had an SSD before, they have a specific set of "caretaking" required which is summed up pretty well here (http://blog.tune-up.com/tips-and-tricks/four-steps-to-optimize-your-ssd/)
 
I have had mine for 2 1/2 years as the OS/Program drive and had it BSOD off and on, but not crash. As the drivers for it became stable it has run smoothly. From my understanding, they do not "crash" in the manner of a magnetic HDD (i.e. catastrophic failure), but the memory cells will degrade over time (they function similar to a massive chunk of RAM). As they degrade, they effectively would become "smaller capacity."
 
When I did research before purchasing mine, the predicted life-span several years, so would meet the same period as I intended to use the machine.
 
If you have never owned one, be sure to research thoroughly, and be sure you get a SATA III (6 Gb/sec) SSD and have SATA III support on your motherboard. An SSD using SATA II only is a waste of money (you won't see "lightning quick" speed out of it).
 
 

Very interesting, thanks for sharing that. TIL

mixmkr
BTW, I'm also under the impression that plugging these other hard drives in and using as needed, is OK and might actually extend their lifespan, as long as I DO use them now and then.....correct?

Are you referring to your external hard disk drives? The highest "stress" on them is parking/unparking the heads, but newer drives park the heads OFF the media so this isn't even much concern anymore (even on loss of power, the last thing it will do it park the heads before they can touch down on the media). So to answer your question, plugging them in and using them when you need them is perfectly OK and what they are designed for.
 
HDD heads actually "fly" ~1 microinch from the platter... so in the OLD days, having them "land" on the media (which is an optical flat) risked them sticking to it (stiction). If the drive powered up again in that condition it risked ripping the head off the arm before it achieved flight. Pretty much any HDD built after 2000 does not have this issue (the heads do not park on platters anymore).

thx mettelus.  I value your answers.  Am I wasting my time plugging and unplugging them? (to extend their potential lifespan)  I actually have more than the # of USB ports available, so some will have to get unplugged anyway.  And they are all USB and none really older than 5 yrs or so...mostly in the 2-3 yr range.

I typically will unplug mine when not being used regularly for a few reasons:
 
   1) Windows will use "bandwidth" to keep communication open to the drive, which is unnecessary if it is not being used. Depending on power management settings, the drives will spin up/go idle as well.
   2) As the purpose of them is for backups, if they are not physically connected to the system, they cannot be damaged by a system level attack.
   3) Windows Indexing functionality can chew up system resources, so if not connected, Windows can't create "undue overhead" by trying to index that drive for you.
 
   Most of these are really to streamline the computer as much as possible when running in "DAW mode" for me. They are certainly not "required," but I feel they are good practice.