Ok. I think I misunderstood your post as saying that DAA may also be useful for people with normal T levels (it's likely not, and there are much better options for this population). I suppose you could try it and get bloodwork using DAA with normal T levels, but it's likely just going to be a waste of time/money/effort. For people with low T is is a much more promising ingredient, and bloodwork would make sense, as you want to see what, if anything, can get you into that normal range, where slight fluctuations within the normal range for a healthy individual isn't really anything to write home about most of the time. If we all had to get bloodwork for every single individual ingredient we use, we'd all be trying one ingredient at a time for years, and spending a good bit of time/money/effort getting constant bloods done, as there are many ingredients people use for "test boosting" or for test-related/associated benefits (DAA, ashwagandha, forskolin, tongkat ali, shilajit, etc). With some ingredients, there is compelling/sufficient research to say that it's quite likely that the ingredient in question will provide some real benefits, meaning that it isn't "necessary" to get bloodwork if you aren't looking to remedy a particular "issue" like low-T. Take ashwagandha for example, there are a ton of studies showing that it can reliably reduce anxiety/stress/cortisol, and also other studies showing benefits in performance/body composition/cognition, etc at the same and/or similar doses, and its affordable, so it's something that makes sense to try and not really necessarily have to be depended on bloodwork to determine if it's doing anyting for you. Similarly, although it's not a test-boosting ingredient, there is so much research on creatine, that it really wouldn't make sense to have to test for anything to see if it works. Granted, some people are non-responders, but that is something you can likely perceive just by using it or not using it over time, and it's also very cheap.
Anyway, that's my latest rant, probably induced by the large amount of stimulants I recently took, and my desire to procrastinate doing actual work haha.