To take the variables out we just send the water sample out to be tested.
If that is what "pond pros" do, then it is almost certainly good advice for amateurs.
What are the components you most commonly get analyzed? What is the ball park cost for that level of testing?
If an amateur does have a pond that is going to require a lot of testing, then I think it would be an excellent idea to confirm that your personal tests closely match with the lab results.
There is an old engineering saying that applies. "The only thing worse than no data, is bad data!"
