I, too notice the large amount of homebrew power supply threads here in the beginner's section, but perhaps from a different perspective. As a beginner myself, I am on the side of having a strong interest in a homebuilt power supply, and I read every thread that comes up about it.
For the more experienced members here who comment on these threads, thanks for answering the same/similar questions over and over again. I do detect a certain amount of frustration at seeing the same threads over and over again, and this is understandable from your perspective. From mine, it is understandable that the threads keep appearing, because I have often thought that no one thread (or even all of them combined) has ever answered most of my questions or put the "simple" issue to rest, so another thread always seems warranted, again from a beginner's perspective.
Because of these things, I actually do ask for a good how-to sticky, or instead of a how-to, a pitfall and what's-what type thread, covering how's and why's, and maybe pointing to some key resources for further learning. I'm trying to walk a line here between asking for spoonfeeding, which nobody wants to do, but getting enough info out into a single point that everyone is satisfied. I myself have done a lot of reading, and think I can handle building a linear supply without burning the house down, so I am not saying it's sticky or bust. We can find the info ourselves, but it would be *nice* to have a sticky as a perfect "jumping off point" to start the learning journey.
Have you noticed how the same "it depends" answers are given? I get it, trust me. It's because IT DOES DEPEND on your intended uses. A sticky that covers this single aspect succinctly would pre-answer a ton of questions. Covering various applications and their associated input/output parameters that a designed must choose prior to actually starting a design. How do I know how much current I want? Voltage range? Why constant current? How many outputs is really needed? How many variable outputs? Can I power them from the same input section? I could go on forever. Once these things are determined, people can provide the information required for a really good answer.