did and stuff does get in though.
You can left the seals (if actually sealed, not all cartridge bearings are) and rins out the grease and repack if you want.
While they are not a smooth and often effected by miss-alignment as cup/cone etc.. they are easy. If your hubs are quality and have alignment all the better, Mavic had adjustment.
You knock them out and tap new ones in. Best to get a shop to do it with bearing setting tools as hitting the outer edge and not the middle damages the bearings (well the races and cage inside).
Most socket sets (the alternate method) are chamfered in the middle and so don't support the middle race... anyways wittering to much without going in to detail.. come to that in a few years time if they are getting worn