I know it from speaking to hundreds of people who have worked through many of these issues. It makes me feel really sad when someone with demonstrably low cortisol on a saliva test is given a tiny dose of HC and fails to improve or feels worse when a full replacement dose could help that person start living life again. Time and time again these same issues come up and a change in form to a longer acting steroid (common issue for those of us with concurrent viral/bacterial infections) or a change in dosing makes all the difference in the world. I would never advocate for one-size-fits-all treatment but there are common places to start based on experience and judgment. I would also never blame anyone (except possibly ignorant doctors who don't know enough about hormone replacement to help guide their patients through it). The only point of any of this is to feel better by properly supporting the endocrine system dysfunctions.