This has me curious on how I would know if my family needs more iodine? We have largely been on kosher salt for a long long time. It is just more pleasant to use while cooking. I could, I think, just switch a lot of what we do back to iodized salt? Feels pointless if not needed, though.
Using "kosher salt" is not always a requirement for a product to be kosher. Technically all salt is kosher if it is produced under kosher supervision, even if it's not "kosher salt".
(And some salt labeled as "kosher salt" can also be not actually kosher!)
"Kosher salt" should be rather called "koshering salt", which is the salt you would use for koshering meat.
And like most people, you likely eat more salt than strictly needed because there's salt in everything. So consuming more salt should be of least concern.