Bought the boat and trailer new in 2002. Still have the original bearings. I keep them well greased. The seals are not leaking. Fish on a average of 3 times a week. At least once a week I have to travel about 1 1/2hrs to fish a lake. When ever I stop I check the hubs for high heat and so far they've been good. So should I change or do not fix what is not broken. What is the longest anyone has gone without changeing?