DHEA(s) tests tend to be more acurate, we could also say that it is storage which can be easily used by body, thats why I suggest to test it, altough as I said it earlier testing progesterone is good enough,
now honestly, there are lot of benefts from DHEA including anti-ageing- but you need to know that you will not feel much of it, you'll find lot of post that claim that they felt this and that, but its because they either used combination (like pregnenolone) or their estrogen was lowish so they felt their estrogen levels raise,
rarely people with poor adrenal output "feel" improvement,
overall small amounts like 25 mg are completely harmless and even 50 mg are ok for majority (oral DHEA) and benefits are there but they will not be rally noticed, and they can be used without need to "cycle" it, and it will have major effect on its production in body, and once person stops using it its level will be returned to baseline.
Again, I'm fan of using pregnenolone (or pregnenolone with little bit of DHEA) and that aproach has been proven as best, even onthis forum there are repots that prove that theory.