I'd expect bearings to last many thousands of miles, as they wouldnt normally have side loading on them and are supporting (whatever) parallel. Thing that wrecks them is cack handed thinking a pressure washer* is a good plan.How many miles ?
Bearing do wear in hubs, it's not unreasonable to have a bad bearing now and then.
*Usually after giving them a good spray with grease dissolving GT85 or such
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@OP if you can access one side, you can remove the seal(black bit) and pump new grease into them.