They are really good and are getting good work too. But the problem starts jab woh practice karna chhod dete hai. They should realise that the real test is not in getting good songs but in retaining the quality of your voice.
This is only possible if he/she puts in a few hours of practice every day. Singing is like quenching one's thirst.
Just like drinking water is needed for a parched throat, practice is essential for a singer to survive. However popular or busy, a singer must never forget his regular training.`