The general consensus is not to dose anything you cant test for. Potassium is something which can be tested and quite accurately for, and iodine can be tested but generally very inaccurate.
Tropic Marin's CEO Lou Ekus mentioned before that a reef tank below 1 year old need not worry about trace dosing which i agree, generally new reef tank has more than enough trace and with a lower coral load, don't have to worry about those depleting.
Once hitting the 1 year mark, it could be beneficial to do an ICP test to figure out what needs to be replenished. But if you have been doing regula