When is it best to do stretch and fold versus mechanical kneading?
I can think of one case where yeast doughs shouldn't suffer from mechanical mixing:


If you're going to be rolling out the dough (eg, for filling &amp; making dumpling-like products, or rolling balls for monkey bread), you'd normally end up compressing the air bubbles when rolling it.  Mechanical mixing has the same problem, so the difference between hand-kneaded and mechanical-kneaded shouldn't be noticeable.


I also tend to use a mixer on doughs that have so high of a hydration that they're more batter-like ... but I'm starting to question that practice after your question.  (they're not that hard to stir with a wooden spoon ... it just takes a little time).

Most of the breads that I make in my mixer are enriched breads (lots of butter or milk), and have small bubbles. (what rumtscho refers to as 'cakelike crumb').

I also use a mixer on breads that take so long to knead that I wouldn't make them without a mixer -- it might result in an inferior loaf, but it's either a fresh slightly sub-par loaf, store-bought (which is likely also machine mixed), or no bread at all.  You can work some larger air bubbles back into the mix by not punching it down (or doing it gently), but using a more gentle stretch and fold before shaping and the final proofing.