I just finished repacking my hubs and it made a huge difference. I was checking the hubs (Shimano m475) and the bearings felt really gritty. I know they're not really good hubs to begin with, but I thought they should be a little smoother than they felts so I tore them down and repacked them with new grease. I knew the cone wrenches I got for a few bucks would come in handy and now the hubs are like new again. I never checked the bearings so I can't believe how long I must have been riding them like that. I probably should have replaced the actual balls but the wheels are only about a year and a half old, less than 2000 miles probably? They have not seen much water and there was plenty of grease in the hubs still so I was just wondering if this is just part of some yearly maintenance that needs to be done and what should I do about sealed bearings in higher end wheels such as Mavics.