Thank you for the detailed answer!

Leaving it plugged in all the time will wear it faster than not, so if you leave it plugged in at the desk a lot, just remove the battery to save it!

Really?? I always left it plugged in because I would think the motherboard would spare using it, essentially putting it in back-up mode. that's really disappointing. I knew from previous research that lithium-ions had recharge-cycle lifespans and lost 20% capacity per year, but to think that having AC power present would only make it worse. I'm shocked.

I currently have a 1 TB HDD with 400 GB used. Do laptops usually have an expansion slot for hard disks (as in, would it be likely that mine has one before checking specifications)? Or will I need to make the switch to SDD completely? I know they're much faster than HDDs (mostly for the lack of moving parts, I assume?) but I also know they're a lot more expensive.

I'm currently running performance analysis tests with the Windows Performance Analysis kit on top of running tests on the hardware (SMART checks, memtest) to see if there are too many components wearing down, but if what you say is correct, I shouldn't need to worry that much. The day the RAM card mucked up on me, the screen went all glitchy-like and froze, restarted normally the next restart, then setting it to sleep and back made it enter its eternal slumber before I had to remove the card.

(Do you know of any other testing/software that I can do? I recently found Soluto, but it's not as detailed as XPERF, which is very detailed and will require so much reading.)

If any laptop you're shopping for does NOT name the CPU (make AND model), don't bother. It's going to be trash.

I've seen a lot of those, but always wrote it off as inconsistent and sloppy title making. Are you implying there's a reason these are titled this way? To hide some cheap specs?

Again, thank you for your answer