I used to work in SSD R&D for a memory company.
When I started there in about 2010, SSDs were better than traditional HDDs in every way except price. And they were dropping in price pretty fast.
Since then, the reliability has just gotten better. Y'all have no idea how many different tricks and clever ideas are inside those little things that make them rock solid. If you look at the UBER statistic, which is essentially how often the drive will give you the wrong bit (0 instead of 1 or 1 instead of 0), it's ridiculously small/rare.
One idea that they describe publicly is that on some drives they treat each flash chip in the drive as a mini drive and they stripe data across the chips, so you essentially have a RAID drive system inside a single drive, and the drive can and will automagically do a RAID recovery in the background if the other 50 clever tricks and ideas happen to fail.
I wouldn't worry about drive lifetimes either. mountainsoft's and Animorph's experiences and calculations are typical - for an average user the lifetime of the drive is actually in centuries or even eons. Of course if you're doing hourly backups or video editing or running a commercial website on it, or something else that is truly heavy usage, you'll need to care and figure that out.
One of the reasons drives have come down in price quite a bit is the underlying technology of the memory cell and the manufacturing process. There are three different aspects that all come into play.
First is the number of bits stored in each cell. They used to have (and maybe still do) SLC and MLC. SLC was one bit per cell; MLC was two bits per cell. SLC is faster and lasts longer and is more reliable, but is expensive. Eventually they got MLC reliable enough and fast enough (more tricks and cleverness) that MLC became the most common in the marketplace. They're now doing three and four bits per cell (TLC and QLC I think are the acronyms), which again are slower and less reliable, but with enough speed and other reliability tricks can be good enough for a customer and drop the prices dramatically.
The second thing is just the process size - they're making each cell physically smaller, which helps with speed and cost. (Speed improvement is marginal I think.)
The manufacturing technology improvements are mainly in layering cells vertically. Older flash chips were a single flat sheet of cells in basically a big XY grid. Now they're miniature high rises. Think of how many people you can stack into a square mile of a small Kansas farm town versus a square mile of Manhattan.
The technology is so good that when I left they were talking about only a handful (like less than two dozen - don't remember the exact number) of electrons needed to be moved into or out of the cell in order to store a bit (or four). Really amazing stuff.
Personally I use a single 1T MLC drive of a recent vintage from my former employer. TLC and QLC and 3D NAND all make me a bit nervous, but that's more my conservative personality rather than any legitimate quality concern about the technology.
Regardless of how reliable these drives are, having good backup hygiene is always recommended. I don't do as well as I could or should, but I'm still young at heart and therefore lazy and think it won't happen to me. I just copy a few of my most important files to my Google drive account every so often.
Oh, and I'd stick with one of the top several manufacturers. There are a lot of small SSD companies whose testing and quality strategies may not be up to snuff. When I left the big three were Samsung, Intel, and Micron/Crucial, and I think that's still the case. I'd be comfortable with a drive from any of those three manufacturers.
The other thing that's happening is that most consumer SSD drives are fast enough now to pretty much max out the data bus interface known as SATA-3 on read speeds and are almost that fast on write speeds. The next thing in the marketplace will be PCIe drives. I don't remember the specs on that interface offhand but I think you can get drives that go maybe five or ten times as fast or even faster. There are commercial PCIe drives now and they're migrating into the high end personal space now. If you're a real heavy user, need greater speed, or just like playing on the bleeding edge, they may be for you.
). For example, needing to do a restore from an image, the restoring software may say the data on the drive getting restore to will be lost. Isn't that excessive writing? If the SSD needs more special care during restores, that's a reason for me to pause.
