As others have mentioned, the Studs shouldn't be that hard to change. Let me ask...
Which side of the trailer is this happening on? Now that pretty much everybody now uses right hand threads on both sides, the Left/Driver side poses a problem since driving forwards tends to loosen right hand threads on the left side of a vehicle.
Is this breakage happening not just at one Hub position, but also with the same Wheel? I've never heard of the hub studs not being correctly centered or spaced, but I suppose it could happen. Or, past problems have damaged the wheel, causing repeat failures.
Finally, how much really tight maneuvering to you do? Tandem trailers create extreme side forces on the wheels, tires, hubs, axles then you turn tight on pavement with good traction and "scrub" the tires. We had a tandem axle boat trailer that weighed out about 4000 with boat on it. Two 2000 capacity axles with 13" 4-lug wheels. Broke the passenger side ends off both axles maneuvering the downhill and turn from driveway to street.