You see tangible progress as a 'random generator'? Do you know people who were worse off after chelation when they were almost certain they had mercury toxicity?
Well, consider some cases:
1) What if you tested for mercury and found you had very little inorganic mercury in blood, and your disposal systems worked great. In the same test, you discover that you have a moderate organic mercury load, but your disposal systems work well on that too.
For that situation, the correct solution is probably not to chelate at all, but just to do use an intestinal binder. Why expose yourself to the significant risks of chelation when the test suggests you don't need to do that?
If you didn't test at all, you end up chelating something your body was disposing of on its own, and you are failing to use an intestinal binder so you end up reabsorbing most of what you dispose of through the liver.
2) You test for mercury and don't have significant organic or inorganic mercury in blood, urine, or hair.
Why are you treating for mercury?
If you didn't test, you could go through a lot of agony with chelators, deplete yourself of vital minerals (which I guess you are also not testing for, since by hypothesis you said this person cannot afford to test), etc.
3) You test for mercury and have a significant load of inorganic mercury and you aren't disposing of it well. You chelate for three months and test again. Amazingly, you find that your blood burden is higher not lower, and the follow up test shows you are not disposing of it through liver well at all.
That person probably needs to strengthen their phase I-to-III pathways through liver and take a binder.
If you didn't test, you had no visibility on the fact that you are making yourself worse, and you simply feel bad all the time.
Let me try one other way of looking at this. Say that you have a patient who convinces herself that she has cancer, and wants to self treat with chemotherapy. And her reasoning is that if the chemotherapy makes her feel better, she must have had cancer. Now wouldn't any person say that is insane? A chelator like DMSA can be more toxic than the most benign chemotherapy drugs. Why is it then in principal different? Taking a strong and toxic chemical is something you should only do when you have evidence that your body needs it.
For me it's a no brainer to get information, get a practitioner who knows how to act on that information, and optimize your pathway based on real data. There are a lot of ways to trip up without information.
I respect that most of us live in countries with freedom to make choices, and you and others can choose to self-medicate and evaluate effectiveness by a different path. All I can do is try to communicate reasons why I think more information is a better way to get to a good result.