This is because Flash Cards/SSD’s Storage cells can only take a limited number of writecycles, so doing a full format is just un-needed wear on your media - thereby shortening it’s life unnescessarily.
A card's life time is on the order of 100,000 write cycles up to a million write cycles, though.
Where did you get those numbers?
EDIT: Found a source for this, seen end of my post.
I mean, one million I haven't seen mentioned before but TBH it's not like I am searching for them all the time.
Still, a search gives me for example from the Kingston website:
For Multi-Level Cell (MLC) Flash, up to 3000 write cycles per physical sector based on current lithography process (19nm and 20nm) at the time of this writing. For Single-Level Cell (SLC) Flash, up to 30,000 write cycles per physical sector. For Triple-level Cell (TLC), up to 500 write cycles per physical sector. Lithography of the Flash Memory Die plays a key role in cell endurance and decreases as the size of the die gets smaller. - Note: judging by the 19 - 20 nm lithography being 'current' process this article is slightly outdated.
This is probably a generic (not Kingston product specific) statement. MLC and TLC are probably more common than SLC (most expensive). Note they specify
sectors, much of the info seems to be referring to
cells which I think is rather significant (I think it's where the 100.000 number comes from).
So. maybe the number is higher per single cell, let's say 100.000 cycles for SLC but as soon as a few cells within one sector 'die' practically it means the entire sector is unusable. When ECC can no longer correct I guess and this in turn depends on length of ECC bits.
So people often quote numbers they've picked up somewhere without context. It's hard to determine what they mean without that context.
Now assume MLC. A full format writes to each and every LBA addressable sector, so that's one write cycle for each of those sectors of the 3000 write cycle limit. For TLC chips a full format is an even bigger 'investment'.
Just thinking out loud. Genuinely interested in holes in my reasoning.
1.000.000 write cycle claim: There's a huge discrepancy between write cycles reported by manufacturers and observational data. I have seen the 1000000 number on some occasions, referring to the observational data. Unfortunately I have been unable to find the source for this claim, nor the test parameters (sequential writes or not, over-provisioning etc.). Also articles use write cycles for cells and blocks very inconclusively even in one sentence.
