I manually test the following...
Alkalinity - 12 times a day
Calcium - 8 times a day
Magnesium - 4 times a day
pH - 3 times a day
Salinity - 14 times daily
Ammonia, nitrite, nitrate and phosphate - 6 times a day
Iron - just 2x a day
Iodine - 3x a week
ICP test every other day to make sure my test kits are good
I use 6 different thermometers to watch temperature
I just started testing strontium daily as well and will start potassium next week
Let us know how the tank is in 5 years and if you still do water changes every other day. Been at this long enough to know we'll never see that update. Flex posts like this are dime a dozen. The updates are non existent.
PS - I don't test what I said above and I don't do water changes. Tank is in my build thread.