Had 2 broken Kitchenaid 600 series pro stand mixers with broken worm follower gears. One had jammed and broken while relatively new, so only had to replace worm follower.
2nd one had just worn out. Worm follower teeth very thin all over until they stripped free. I also replaced the worm gear and fiber washer on planetary set, due to wear.
Very simple mechanical fix, if a bit messy. I used Super Lube 41160 UV synthetic food grade grease from that big online retailer named after the South American river.
By far the biggest time spent was cleaning out old grease/bits of gear teeth from gearcase.