Are you serious? The cost of sending out a test every month makes you hesitant? Why? It's $50. Once things are dialed in you do not have to test every month if you dont want to. Almost all of us do not test our water this way now.... So even once every 3 months is a vast improvement! I do not mind testing every month. I guess the value of our corals and the overall health of our tanks can vary from people to people. My tank worth ALOT more than $50 or even $100 per month to me.
Some of us if not alot of us spend way more money on salt mix and RODI filters per month than the elementz solutions + test. Anyhow, it's a matter of opinion and subjective values. I personally think it is the best method in reef keeping for ME. I have been dosing for 3 weeks now and things are looking awesome.
Kid
The point of the salt mix and RODI is very valid. The costs may not equal (depending on RODI exhaustion and salt mix cost, as well as tank size) but in some cases could be equal. When you consider these costs, the Triton method does seem to become more economical then looking at it in a vacuum.
Take my system for example, 150g total volume. 2% daily water changes would be 90 gallons per month. Thats roughly $35/month for Red Sea salt alone, not factoring in the DI resin in my RODI (which is consumed quite fast since my TDS is over 700 in my tap water). Right now I am consuming a set of Elementz about every 2 months, plus a triton test each month: ~$80/month.
For me, Triton is worth a lot more then that if only for the increased knowledge I gain about my system. Being able to see the true status of all these tank parameters over time is incredible and has countless benefits (including seeing bad things building up that may crash your tank).