I'm experiencing an annoying problem with my rear hubs. They're pretty standard Shimano hubs with quick releases (one's a Deore, others are Deore XT). They seem to develop some play after short (~5 mile) rides, even if the cones and quick-release seem to be well-adjusted before each ride. I think the problem might lie in how I tighten the locknut in small increments while checking for play. I think that I might not be able to detect tiny amounts of play at the rim, so I might be under-tightening the skewer. But I don't understand why the hub develops more play as I ride. Is this bound to happen if I undertighten the skewer?
While I'm at it, I might as well ask how tolerant cup and cone hubs are to overtightening. I suppose this might depend on the thread pitch of the skewer, but does it make much of a difference to the hub's longevity if I tighten an eighth of a turn past "just right"?