I dont see how they would repeatedly loosen up? Maybe once on a new set of bearings, but not usually. As long as the races are good, no discoloration or grooves on surface, and the bearings are good and well packed, you shouldnt have a problem. I usually install everything tighten the castle nut down while spinning the wheel by hand, until hard to spin, then loosen slightly. I do this a couple of times if new bearings and races were used.
Never had this problem, have done misc different old ford cars and trucks and thousands of trailer hubs of many sizes.
Best of Luck!!
