Most opera singers who add demanding roles to their repertoires at a young age lose their voices early  It has been said that this is because their voices have not yet matured and hence lack the power for such roles  But young singers with great vocal power are the most likely to ruin their voices  The real problem is that most young singers lack the technical training necessary to avoid straining their vocal cords -- especially when using their full vocal strength
Such misuse of the cords inevitably leads to a truncated singing career
Only mature opera singers can sing demanding roles without undue strain on their vocal cords.