Nick Walsh's reation to Simuai's article Nesting Components (which covers eight possibilities for the simple task of styling elements within other elements):
the very nature of CSS leaves many problems without an exact solution, and the right one for you won't always work for others. If you write, speak, or otherwise communicate about stylesheets, don't be afraid to offer an open-ended answer.
Philip Walton reacts to the same article:
While I share his desire to nail down the best strategy (and I do have an opinion on the subject), I think it's actually more valuable to discuss how one might approach answering this question rather than what the actual answer may be.