Sometimes their magazines have nothing more than detailed instructions on disassembly along with a few comments here and there about problems. Problem is, if you've been around long enough, you will have a general understanding of how to disassemble just about any gun and put it back together too.
Of late though there have been some more how-to or work bench type articles from members. These are insights which can be invaluable. In the past was a two part article on how to make fibre-glass stocks, something which I suspect was offered to TFL members two years ago (boy, were we young then) at $10.
Summing it up, it all depends on what level of experience or expertise you're at. It also depends on what type of machinery you have available. It's no good to read about milling out a part and not having access to a mill. Further, for a reader with absolutely no machine shop experience, some material may go right over their head.