Kneading bread dough is one of the best things to do with a stand mixer. But there are limits. Using too high a speed while kneading can overtax, even damage, your machine. Manufacturers typically recommend going no higher than low or medium-low (Speed 2 or 3, depending on the model) with yeast doughs. With softer bread dough, say, something like challah, I’m okay with pushing closer to medium if I’m really trying to bring the ingredients together. You can even briefly increase the speed to medium and drop it back down once things are better incorporated. Remember that beyond the risk to your machine, you can overknead the dough. If your dough is especially stiff, as with bagels, stick with the lower end of the spectrum.