When a teenager starts singing young like on idol, do their voices last long?

Singing voice: Yes it does as long as you do not strain your voice by singing the notes you can not reack.Even if you are able to sing at an early age you still need to train your voice properly and if you do not do that then you can harm your vocal cords and end up in a bad way.So keep singing but get proper voice training which includes breathing teqniques and proper way to sing without damaging vocal cords.

Style matters: A trained singer can go for 70+ years singing if they have good technique and healthy habits. If the contestants on ai have such a background, they can absolutely last. Unfortunately, many don't and are imitating the 'belting' they think they hear from stars. I hope that the show provides them with opportunities to rest and medical attention when needed.