Some of the problem may be caused from lack of use, especially if they had not been serviced since 2009. A lot of trailers are used infrequently for weekend trips. As they sit, the grease will separate and no longer lubricate. Was the second failure on the same wheel? This happened on my 24' years ago and the heat from failure warped the spindle. Had two more failures before I changed the axle, which cured the problem. Check the axle brand and model, some of the spindles can be replaced without changing the entire axle. Replacement wasn't even all that expensive.