I posted about this some time ago but hadn’t found any useful way of doing it sensibly. There is a huge amount of spare space on mine so no rush.
Looking around I found this page which gives some details on hows and why’s. I thought that given the problem there must be a command to generate the data that’s needed and do it when needed.
How to properly activate TRIM for your SSD on Linux: fstrim, lvm and dm-crypt | synaptic fault
Still no method of telling when it’s needed and I suspect there must be some where.
Thank You very much for this one John! Coming from a Fedora install with LVM I now understand why the trim
command seemed to do nothing.