the voice is an instrument, it neds to be practised,just as an instrument does.
the voice and the lungs will not take continued abuse[cigarette smoke is number one offender]
as regards technique my advice to younger singers would be to learn good diaphragm control, and learn breathing exrcises which will devolp your lungs, at the same time listen to good traditional singers such as harry cox and phil tanner, margaret barry and sara makem.