Most places I've been they mill it themselves. My favorite place we get to weigh out and mill our own grain. I love being able to sample some of the grain as I goI buy grains from 2 different lhbs. At the old lhbs (Phantom Ales), customers are allowed to weigh and mill their own grains, but they do not permit gap adjustment. There, I always run my grains through twice. At the new lhbs (Windsor Home Brew Supply) they do the weighing and the milling of the grains. Their mill is fancy, and has a setting that is great for BIAB, so I request that setting. Either way works for me, and beer gets brewed.