Originally Posted by wmodavis

+1 to most of what noglider said.
A minor clarification IMO is that it is not 'to much tension' that roundsoff the spokes, rather it is because of a wrong sized or cheap spoke wrench, not lubricating the spoke threads and nipple/rim interface, and/or using aluminum nipples that contributes to the rounded nipples. Of course, it is aggravated because at higher tensions (which is of supreme importance to achieve a strong, durable wheel) more torque must be applied, and the mentioned causes will likely do in the nipples.