[gentoo-user] "Amount" of fstrim? (curiosity driven, no paranoia :)

Hi,

jyst out of curiosity:

I have a 512 MB NVMe SDD drive installed, which I had (currently)
formatted with one 256 MB root partition.
I bound /var and /tmp to hardisk.

Currently I am doing one Gentoo update a day and I am running
unstable.

Just to get a feeling, how often I need to fstrim / I do it
currently by hand once in a week.

Fstrim reports about 200 GiB of trimmed data.

From the gut this looks quite a lot -- the whole
partition is 256 GB in size.

Smartclt report for the drive:
Data Units Written:                 700,841 [358 GB]

Each week 200 GiB fstrimmed data for a partition of
256 GB in size and since the beginning I have written
only 358 GB to it.

How does this all fit together?

Cheers!
Meino